Eye covering and refractive correction methods and apparatus having improved tear flow, comfort, and/or applicability

ABSTRACT

An eye covering such as a contact lens may comprise one or more structures to pump tear liquid under the covering such that the covering can remain in the eye and correct vision for an extended amount of time. In many embodiments, the covering comprises a material having fenestrations to draw tear liquid under the covering and an outer portion shaped to contact the conjunctiva over the sclera, such that when the eye closes pressure of one or more eyelids urges tear liquid through one or more fenestrations and under the outer portion shaped to contact the conjunctiva. When the eye blinks, the pressure of the one or more eyelids can urge the covering toward the cornea such that tear liquid can pass through the fenestrations

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/468,075 filed on Aug. 25, 2014, now allowed, which is a divisional ofU.S. application Ser. No. 13/456,168, filed on Apr. 25, 2012, issued asU.S. Pat. No. 8,864,306, which claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 61/636,404 filed on Apr. 20,2012, U.S. Provisional Application No. 61/507,971 filed on Jul. 14,2011, and U.S. Provisional Application No. 61/480,222 filed on Apr. 28,2011, each of which is incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

The present invention is generally directed to vision and treatment ofthe eye to provide improved vision. Although specific reference is madeto coverings for vision correction such as the correction of refractiveerror and also to treatment of eyes having epithelial defects followingphotorefractive keratectomy, embodiments of the present invention maycomprise extended wear contact lenses that can be used to correct visionin many ways such as with one or more of aberration correction,multifocal correction, presbyopia correction, and astigmatismcorrection.

The eye includes several tissues that allow patients to see. The corneaof the eye is an anterior tissue of the eye that is clear in healthyeyes and refracts light so as to form an image on the retina. The retinais a posterior tissue of the eye that senses light from the image formedthereon and transmits signals from the image to the brain. The corneaincludes an outer layer of tissue, the epithelium, which protects theunderlying tissues of the cornea, such as Bowman's membrane, the stromaand nerve fibers that extend into the stroma and Bowman's. The healthyeye includes a tear film disposed over the epithelium. The tear film cansmooth small irregularities of the epithelium so as to provide anoptically smooth surface. The tear film is shaped substantially by theshape of the underlying epithelium, stroma, and Bowman's membrane, ifpresent. The tear film comprises a liquid that is mostly water and doesinclude additional components, such as mucoids and lipids. The manynerve fibers of the cornea provide sensation to promote blinking thatcan cover the cornea with the tear film. The never fibers also sensepain so that one will normally avoid trauma to the cornea and also avoiddirect contact of an object to the cornea so as to protect thisimportant tissue.

Work in relation to embodiments of the present invention suggests thatat least some of the prior contact lenses and therapeutic coverings canbe less than ideal in at least some instances. Many contact lenses andtherapeutic coverings can be left in the eye for less than idea amountsof time, as the patient removing and replacing the contact lens ortherapeutic covering can be somewhat cumbersome and in at least someinstances patients may leave the contact lens or therapeutic covering inthe eye for amounts of time that can be longer than would be ideal.Although extended wear lenses can be left in the eye for somewhat longeramounts of time, the amount of time such lenses can be left in the eyecan be less than ideal. Work in relation to embodiments of the presentinvention also suggests that tear flow of the prior contact lenses canbe less than ideal, and that less than ideal tear flow may be related tothe potential complications and can limit the amount of time such lensescan be left in the eye.

In the healthy cornea, the proper amount of hydration of the cornea,sometimes referred to as dehydration of the cornea, is maintained suchthat the cornea remains clear. The cornea includes a posteriorendothelial layer that pumps water from the cornea into the adjacentanterior chamber. The epithelium inhibits flow of water from the tearliquid into the cornea, such that the corneal stroma can be maintainedwith the proper amount of hydration with endothelial pumping. Theendothelial pumping of water from the cornea to maintain the properhydration and thickness of the eye is often referred to asdeturgescence. When the corneal epithelium heals, the layer of cellsforming over the defect can be at least somewhat irregular in at leastsome instances, such that the vision of the patient can be less thanideal.

As the post-ablation cornea may have a complex shape, many of the priorcommercially available lenses may not fit the ablated cornea as well aswould be ideal, and in at least some instances fitting of lenses can betime consuming and awkward. Commercially available contact lenses havinga rigid central RGP portion and a soft peripheral skirt can be difficultand/or time consuming to fit to the ablated cornea and may not fit verywell in at least some instances. The ablated cornea may comprise anabrupt change in curvature near the edge of the ablation, and in atleast some instances it can be difficult to fit such lenses near theedge of the ablation. Also, at least some of the commercially availablecontact lenses may not be suitable for extended wear and may be removedeach day, which can be somewhat awkward for a patient and can result inlack of compliance and lenses remaining in the eye longer than would beideal in at least some instances.

In light of the above, it would be desirable to provide improved contactlenses for vision correction and coverings for treatments related toepithelial defects of the cornea, such as epithelial defects followingPRK. Ideally, these contact lenses and coverings would providetreatments that improve tear flow and avoid at least some of thedeficiencies of known techniques while providing improved patientcomfort and/or vision.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention provide an improved coverings thatprovide improved vision for extended amounts of time and can be usedtreat normal eyes or eyes having an epithelial defect, such as anepithelial defect subsequent to refractive surgery such as PRK. Thecovering may comprise a contact lens and can provide improved tear flowsuch that the covering can be left on the eye to correct vision forextended amounts of time. The covering may comprise a water inhibitinglayer and one or more structures to pump tear liquid under the waterinhibiting layer of the covering such that the covering can remain inthe eye and correct vision for an extended amount of time. Alternativelyor in combination, the covering may comprise a hydrogel layer extendingalong a posterior surface of the covering coupled to the fenestrationsto provide hydration and patient comfort. The hydrogel layer may fluidlycouple the cornea to the fenestrations so as to pass tear liquid andtherapeutic agents from an anterior surface of the covering through thefenestrations and hydrogel to the cornea. In many embodiments, thecovering comprises a material having fenestrations and an outer portionshaped to contact the conjunctiva to pump tear liquid when the eyeblinks. The covering may comprise a deflectable outer portion having aresistance to deflection such that a chamber is formed when the coveringis placed on the eye and the eye is open with the eyelids separated. Ahydrogel layer coupled to the fenestrations may extend along a lowersurface of the covering at least a portion of the chamber. Theresistance to deflection of the deflectable outer portion can beconfigured such that the outer portion deflects inward toward the corneawhen the eyelid closes to pump tear liquid. The fenestrations can drawtear liquid into the chamber located under the covering when the eyeopens and the chamber can expands. The fenestrations may extend throughthe hydrogel layer to provide pumping. Alternatively or in combination,the hydrogel layer may cover the posterior end of the fenestrations andthe deflection of the outer portion can encourage movement of liquid andmedicament along the hydrogel. The outer portion of the coveringcomprises a sclera coupling portion shaped to contact the conjunctiva todefine the chamber when the covering is placed on the eye. Thefenestrations and sclera coupling portion of the covering can pass tearliquid away from the chamber when the eye closes and pressure of one ormore eyelids urges the covering toward the cornea such that the chambervolume decreases. In many embodiments, opening of the eye so as toseparate the eyelids reduces pressure on the outer portion of thecovering such that the outer portion of the covering over an outerportion of the cornea can separate from the outer portion of the corneaso as to draw liquid through the fenestrations and into the chamberlocated under the covering. The sclera coupling portion of covering maycontact the conjunctiva to inhibit the flow of tear liquid under thesclera coupling portion when the eye opens and tear liquid is drawnthrough the fenestrations, for example with formation of a seal wherethe covering contacts the conjunctiva. When the eye blinks subsequently,the pressure of the one or more eyelids can urge the covering toward thecornea such that tear liquid can pass through the fenestrations, and thesclera coupling portion may separate slightly from the conjunctiva topass tear liquid under the sclera coupling portion, so as to rinse thecornea, the limbus, the conjunctiva and the underside of the coveringwith the pumped tear liquid. The covering may comprise a material havinghigh oxygen permeability such as silicone such that the covering mayprovide improved tear flow and high oxygen permeability. This improvedflow of tear liquid can allow the covering such as a contact lens to beworn for extended amounts of time of at least about one week, forexample thirty days or sixty days or more. The improved tear flow canimprove healing and vision of eyes with epithelial defects, for exampleepithelial defects following PRK.

In many embodiments, the covering comprises an inner optical componentfor vision, such as a lens, and an outer coupling component to hold theinner component in relation to the pupil to improve vision. The couplingcomponent may comprise a deflectable material that inhibits passage ofthe tear liquid through the material such that the tear liquid passesthrough the fenestrations when the eye blinks and an eyelid exertspressure on the optical component. The outer coupling component maycomprise the fenestrations to pass the tear liquid and the outer scleracoupling portion to contact the conjunctiva. The optical component maycomprise a first material and first thickness corresponding to a firstrigidity. The coupling component may comprise a second material and asecond thickness corresponding to a second rigidity. The second materialcan be softer than the first material and the second thickness can beless than the first thickness such that the coupling component is can bedeflected with the eyelid, and such that the coupling component can bedeflected by an amount greater than the optical component when theeyelids close to cover the first component and the second component. Theoptical component can be more rigid than the coupling component, suchthat the optical component can provide vision when the outer portion isdeflected with one or more eyelids.

The alignment of the optical component to the pupil provided with thecoupling to the conjunctiva and underlying sclera can be beneficial forvision. The optical component can be held at a substantially fixedlocation in relation to the pupil so as to provide improved vision suchas presbyopia correction and vision correction of aberrations that maydepend on location of the pupil such as measured wavefront aberrations,spherical aberration, coma and trefoil.

The optical component and coupling component can be helpful to improvevision and regeneration of the epithelium in eyes with epithelialdefects. The optical component can smooth the cornea and may smoothirregularities of the epithelium and ablated stroma. The couplingcomponent can support the optical component so as to resist slidingmovement of the optical component and provide an environment to promoteregeneration of the epithelium. The pumping of the tear liquid mayimprove tear flow to the regenerating epithelium near the epithelialdefect so as to promote regeneration of the epithelium over the defect.The pumping of the tear liquid can also promote delivery of amedicament, for example a steroid, to the ablated region so as toinhibit corneal infiltrates and haze.

In a first aspect, embodiments of the present invention provide acovering to treat an eye of a patient. The eye has a tear liquid, apupil, a cornea, and a conjunctiva. The covering comprises an opticalcomponent to correct vision of the eye and a coupling component. Theoptical component comprises a first rigidity sufficient to resistdeformation when placed on the eye. The coupling component contacts thecornea and the conjunctiva and supports the optical component inrelation to the pupil. The coupling component comprises an outer portionsized to contact the conjunctiva, an inner portion to couple to theoptical component, and an intermediate portion extending between theinner portion and the outer portion. One or more of the opticalcomponent or the coupling component comprises a plurality offenestrations to pump the tear liquid when the eye blinks.

In many embodiments, the covering comprises an inner portion comprisingthe optical component and the inner portion of the coupling component.An outer portion of the covering may comprise the intermediate portionof the coupling component and the outer portion of the couplingcomponent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an eye suitable for use with the covering as describedherein, in accordance with embodiments of the present invention;

FIG. 1-1A shows an ablated eye immediately following refractive surgeryresulting in an epithelial defect, suitable for incorporation inaccordance with embodiments of the present invention:

FIG. 1A1 shows a covering positioned on an eye and blinking of the eye,in accordance with embodiments of the present invention:

FIG. 1A2 shows the covering of FIG. 1A1 that is capable of pumping tearliquid under the covering, in accordance with embodiments of the presentinvention:

FIG. 1A3 shows a schematic illustration of the covering of FIGS. 1A1 and1A2 pumping tear liquid when the eye closes, in accordance withembodiments of the present invention;

FIG. 1A4 shows a schematic illustration of the covering of FIGS. 1A1 and1A2 pumping tear liquid when the eye opens, in accordance withembodiments of the present invention;

FIG. 1B1 shows a covering having a tricurve profile to fit sclera, whichcovering may be used to fit an ablated cornea, in accordance withembodiments of the present invention;

FIG. 1B2 shows a covering having a tricurve profile to fit sclera withslopes of the curved profiles aligned so as to inhibit ridges at theboundaries of the curved portions, in accordance with embodiments of thepresent invention;

FIG. 1B2-1 shows alignment of the slope of the lower surface of thecorneal contacting portion with the slope of the lower surface of thesclera coupling portion, such that pressure to the limbus is decreasedsubstantially, in accordance with embodiments of the present invention;

FIG. 1B3 shows a tapered edge of the covering of FIG. 1B1, in accordancewith embodiments of the present invention;

FIG. 1B4 shows a plan view covering having a tricurve profile to fit thecornea, limbus and sclera with slopes of the curved profiles aligned soas to inhibit ridges at the boundaries of the curved portions, inaccordance with embodiments of the present invention;

FIG. 1B5 shows a side sectional view of the covering of FIG. 1B4 andcorresponding curved portions to couple to the cornea, limbus andsclera, in accordance with embodiments of the present invention;

FIG. 1B6 shows a side sectional view of the covering of FIG. 1B4 andcorresponding curved portions of the upper surface, in accordance withembodiments of the present invention;

FIG. 1B7 shows a tapered edge of the covering of FIG. 1B4, in accordancewith embodiments of the present invention;

FIG. 1C shows a covering comprising a single piece of material having aninner thickness greater than an outer thickness, in accordance withembodiments of the present invention;

FIG. 1C1 shows a covering as in FIGS. 1-2A to 1B2 having an innerportion comprising an inner thickness and an inner material and an outerportion comprising an outer thickness and an outer material, in whichthe inner thickness is greater than the outer thickness, in accordancewith embodiments of the present invention;

FIG. 1C2 shows a covering as in FIGS. 1-2A to 1B2 having an innerportion comprising an inner thickness and an inner material and an outerportion comprising an outer thickness and an outer material, in whichthe inner thickness is greater than the outer thickness and the outermaterial extends around the inner material, in accordance withembodiments of the present invention;

FIG. 1C2A shows a covering as in one or more of FIGS. 1-2A to 1B7 havinga layer of hydrogel material on a posterior surface of the covering, inaccordance with embodiments of the present invention;

FIG. 1C2B shows a covering as in one or more of FIGS. 1-2A to 1B7 havinga layer of hydrogel material on a posterior surface of the coveringextending less than a maximum distance across the covering such that endportions of the covering are configured to engage the epithelium of theeye away from the hydrogel layer and inhibit movement of the coveringwhen placed on the eye, in accordance with embodiments of the presentinvention;

FIG. 1C2C shows a covering as in one or more of FIGS. 1-2A to 1B7 havingan annular layer of hydrogel material on a posterior surface of thecovering such that an inner portion of the covering contacts the corneaaway from the hydrogel layer and an outer portion of the coveringcontacts the cornea away from the covering when placed on the eye, inaccordance with embodiments of the present invention;

FIG. 1C3 shows a shows a covering having a tricurve profile to fitsclera with slopes of the curved profiles aligned so as to inhibitridges at the boundaries of the curved portions as in FIG. 1B2 andhaving a layer of hydrogel material on a lower surface, in accordancewith embodiments of the present invention;

FIG. 1C4 shows a plan view covering having a tricurve profile to fit thecornea, limbus and sclera with slopes of the curved profiles aligned soas to inhibit ridges at the boundaries of the curved portions as in FIG.1B4 and having a hydrogel material on a lower surface extending lessthan a maximum distance across the covering to engage the conjunctivawith the covering away from the hydrogel material, in accordance withembodiments of the present invention;

FIG. 1C5 shows a fenestration having a posterior end covered with alayer of hydrogel extending along the posterior surface of the covering,in accordance with embodiments of the present invention;

FIG. 1C6 shows a fenestration extending through a layer of hydrogelextending along the posterior surface of the covering, in accordancewith embodiments of the present invention;

FIG. 1D shows a covering comprising channels extending radially outwardalong a lower surface of the covering, in accordance with embodiments;

FIG. 1E shows a covering comprising channels extending radially inwardalong a lower surface of the covering, in accordance with embodiments;

FIG. 1F shows a test apparatus to measure deflection of a portion of alens in response to a load, in accordance with embodiments;

FIG. 2A shows a covering comprising a contact lens placed on the eyewith the eyelids separated, in accordance with embodiments;

FIG. 2B shows a side sectional view of the covering of FIG. 2A with theeyelids closing, in accordance with embodiments;

FIG. 2C shows a front view the covering of FIG. 2A with the eyelidsclosing, in accordance with embodiments;

FIG. 2D shows side profile the covering of FIG. 2A with the eyelidsopening, in accordance with embodiments;

FIG. 2E shows a covering comprising a contact lens placed on the eyesuch that the covering is supported with an inner portion of the corneaand the conjunctiva with the covering separated from an outer portion ofthe cornea so as to define a chamber when the eyelids are separated, inaccordance with embodiments;

FIG. 2F shows a side sectional view of the covering of FIG. 2E with theeyelids closing, in accordance with embodiments;

FIG. 2F1 shows a side sectional view of the covering of FIG. 2F withrotation of the eye when the lids close such that sliding of thecovering along the epithelium is inhibited when tear liquid is pumped,in accordance with embodiments;

FIG. 2G shows a side view sectional view of the covering of FIG. 2E withthe eyelids opening, in accordance with embodiments;

FIG. 2H shows a side view sectional view of the covering of FIG. 2E withthe eyelids located at an intermediate location such that the chambercomprises an intermediate volume, in accordance with embodiments;

FIG. 2I shows a side view sectional view of the covering of FIG. 1C4placed on the eye with hydrogel contacting the eye, in accordance withembodiments;

FIG. 3A shows a covering positioned on cornea an eye having anepithelial defect, in accordance with embodiments;

FIG. 3B shows a covering in a first configuration prior to placement oncornea of an eye having an epithelial defect, in accordance withembodiments;

FIG. 3C shows the covering of FIG. 3B placed on the eye having a secondconfiguration, in accordance with embodiments;

FIG. 4A shows a mold to form an optical component of a covering;

FIG. 4B shows a mold to form a covering comprising the optical componentof FIG. 4A;

FIG. 4C shows a mold to form a covering comprising the optical componentof FIG. 4A and a layer of a soft material of the covering;

FIG. 4D shows a mold to form a covering and having a solid innercomponent comprising the rigid material placed therein prior toinjection of a flowable material, in accordance with embodiments of thepresent invention;

FIG. 4E shows formation of fenestrations in the covering with energy, inaccordance with embodiments of the present invention;

FIG. 4F shows spin coating of a hydrogel material on a posterior surfaceof the covering, in accordance with embodiments of the presentinvention;

FIG. 4G shows chemical vapor deposition on the covering having thehydrogel material formed thereon, in accordance with embodiments of thepresent invention; and

FIG. 4H shows the covering comprising the hydrogel material packaged ina container, in accordance with embodiments of the present invention.

FIG. 5 shows a covering in accordance with certain embodiments.

FIG. 6A shows views of radials for an example of a hard lens positionedon an astigmatic eye.

FIG. 6B shows views of radials for an example of a soft lens positionedon an astigmatic eye.

FIG. 6C shows views of radials for an example of a covering according tocertain embodiments of the present invention positioned on an astigmaticeye.

DETAILED DESCRIPTION OF THE INVENTION

Embodiments of the present invention as described herein can be combinedwith the therapeutic covering device for pain management and vision asdescribed in U.S. Pat. App. Ser. No. 12/384,659, filed Apr. 6, 2009,entitled “Therapeutic Device for Pain Management and Vision”, the fulldisclosure of which is incorporated herein by reference and suitable forcombination in accordance with some embodiments of the present inventionas described herein.

As used herein, a covering is used to refer to an ophthalmic device thatcovers an eye of a patient and that does not by itself providerefractive vision correction. Ophthalmic devices that provide refractivecorrection are referred to herein as contact lenses or ophthalmiclenses.

The embodiments described herein can be used to treat eyes in many wayswith a covering such as a contact lens. The covering described hereincan be used for long term vision correction with extended wear contactlenses that inhibit swelling of the cornea when the covering ispositioned on the eye for an extended period, and may also be combinedwith many forms of ocular surgery, such as photorefractive keratectomy.

As used herein, mathematical equations and scientific notation can beused to values in many ways understood by a person of ordinary skill inthe art, for example so as to express data in accordance with notationsused in many commercially available spreadsheets such as Excel™commercially available from Microsoft. As used herein the symbol “E” canbe used to express an exponent in base 10, such that 1E1 equals about10, 2E1 equals about 20, and 4E2 equals about 400. As used herein thesymbol “{circumflex over ( )}” can be used to express an exponent, suchthat A{circumflex over ( )}B equals A^(B). Units can be expressed inmany ways and as would be understood by a person of ordinary skill inthe art, for example “m” as meters, “Pa” as the Pascal unit forpressure, “MPa” as Mega Pascal.

As used herein, a siloxane bond encompasses a covalent Si—O—Si bond, forexample of a silicone elastomer.

As used herein, an on K fit of a covering such as a contact lensencompasses fitting the contact lens to the flattest meridian of thecornea to and the on K fit can be flatter than the flatters meridianwithin about 1.5 D. For example, for a cornea having keratometer values(hereinafter “K's”) of about 44D axis 90 and 43D axis 180, the on K fitwould fit would provide a covering having a curvature corresponding toan optical power within a range from about 43D to about 41.5 D for theregion of the eye measured. The on K fit as described herein can allowfor tear liquid to form under the covering such that the tear liquid canbe pumped in accordance with embodiments as described herein.

The optical power of the cornea in Diopters (“D”) can be related to theradius R of curvature with the formula D=(1.3375-1)/R, where 1.3375corresponds to the index of refraction of the aqueous humor and Rcorresponds to the radius of curvature of the cornea. The curvature ofthe cornea is inversely related to the radius of curvature R such thatas the radius of curvature increases the curvature of the corneadecreases and such that as the radius of curvature decreases thecurvature of the cornea increases.

FIG. 1 shows an eye 2 suitable for use with the covering 100 asdescribed herein. In many embodiments, covering 100 comprises a contactlens. The eye has a cornea 10 and a lens 4 configured to form an imageon the retina 5, and the image can form on a fovea 5F corresponding tohigh visual acuity. The cornea can extend to a limbus 6 of the eye, andthe limbus can connect to a sclera S of the eye. The eye 2 has a parsplana PP located near limbus 6. A conjunctiva C of the eye can bedisposed over the sclera. The lens can accommodate to focus on an objectseen by the patient. The eye has an iris 8 that defines a pupil 9 thatmay expand and contract in response to light. The eye also comprises achoroid CH disposed the between the sclera 7 and the retina 5. The eyehas a vitreous humor VH extending between the lens and the retina. Theretina 5 senses light of the image and converts the light image toneural pulses that are processed and transmitted along an optic nerve ONto the brain of the patient.

FIG. 1-1A shows an ablated eye immediately following refractive surgery,for example PRK surgery resulting in an epithelial defect. The coveringcomprising the contact lens as described herein can be placed over theablated cornea and coupled to the conjunctiva to provide improvedvision. The eye 2 comprises an iris 8 that defines a pupil 9, throughwhich light passes such that the patient can see. Cornea 10 includes anepithelium 12 disposed over a stroma 16. The epithelium 12 comprises athickness 12T that can be about 50 μm. A tear liquid covers the anteriorsurface of epithelium 12. In at least humans, primates and some birds, aBowman's membrane 14 is disposed between epithelium 12 and stroma 16.Bowman's membrane 14 comprises an a cellular substantially collagenoustissue with a thickness of about 5 to 10 microns. Stroma 16 comprises asubstantially collagenous tissue with keratocytes disposed therein. Insome animals, Bowman's membrane may be absent and the epithelium may bedisposed adjacent to the stromal layer. An endothelium 18 is disposedunder stroma 16. Endothelium 18 comprises a layer of cells that pumpwater from cornea 10 toward iris 8. Tear liquid also covers surfaces ofthe cornea that are exposed by the epithelial defect, such as an exposedsurface of Bowman's membrane and an exposed stromal surface.

With refractive surgery, for example PRK, the epithelium can be removedto ablate a refractive correction into Bowman's membrane 14 and/orstroma 16. An initial profile of the anterior surface of stroma and/orBowman's membrane is ablated to an ablated profile 20 to correct thepatient's vision. The profile of tissue removed to correct vision isdescribed in U.S. Pat. No. 5,163,934, entitled “Photorefractivekeratectomy”, the disclosure of which may be suitable for combination inaccordance with some embodiments of the present invention describedherein. Ablated profile 20 generally comprises an optical zone thatextends across the cornea to correct refractive error of the eye and maycorrect aberrations of the eye, for example wavefront aberrations.Ablated profile 20 is bounded by boundary 20B that may circumscribe theablated profile. The ablation profile 20 comprises a maximum dimensionacross, for example a diameter 20D.

The epithelium may comprise an inner boundary that moves centripetallyinward as indicated by arrows 30.

In many embodiments as described herein, irregularities of the corneaare decreased when the epithelium regenerates so as to provide one ormore of improved vision or comfort. The coverings as described hereincan be configured so as to decrease an effect on vision of cornealirregularities.

FIG. 1A1 shows covering 100 positioned on a blinking eye. An upper lidand a lower lid can blink over the eye. Work in relation to embodimentssuggests that the upper lid can exert a downward movement 22A and thatthe lower lid can exert an upper movement 22B on the eye. The downwardmovement 22A can be greater than the upper movement 22B. The wettablecoating material as described herein can decrease force and movementtransferred from the lids to the covering so as to inhibit motion of thecovering.

FIG. 1A2 shows the covering of FIG. 1A1 that is capable of pumping tearliquid under the covering. The covering 100 has inner portion 110 andouter portion 120, and fenestrations 100F extending through thethickness of the covering on the outer portion so as to tear liquid TL,which may comprise a medicament. The medicament may comprise ananesthetic, an analgesic, or other medication, for example.

The covering 100 comprises an optical component 100A and a couplingcomponent 100B. The optical component 100A may comprise an inner portion110 of covering 100 and the coupling component 100B may comprise anouter portion 120 of covering 100. The optical component 100A comprisesrigidity sufficient to resist deformation such that the opticalcomponent 100 can correction vision of the eye. The optical component100A may comprise a single layer of material, or a plurality of layersof materials. The coupling component 100B may comprise a rigidity lessthan optical component 100A, such that the coupling component can one ormore of deflect or elastically deform so as to conform to the corneawhen covered with the eyelid. The coupling component 100B may comprisean inner component 100B1 to couple to the optical component, an outerportion 100B3 to couple to the sclera, and an intermediate portion100B2. The intermediate portion 100B2 can extend between the innercomponent 100B1 and the outer component 100B3 so as define a chamberwhen placed on the eye.

The optical component 100A and the coupling component 100B can pump tearliquid under the cornea when the eye closes and opens, for example whenthe eye blinks. The outer component 100B comprising outer portion 120may comprise fenestrations 100F. For example, the intermediate portion100B2 may comprise fenestrations 100F. The outer portion 120 maycomprise outer portion 100B3 comprising a sclera coupling portion 130 tocontact the conjunctiva over the sclera and peripheral portion 120P. Thesclera coupling portion 130 may comprise a thin flange portion extendingto the peripheral portion 120P. The sclera coupling portion may comprisea thin elastic portion capable of elastic deformation when the eyeblinks to allow the optical component to move downward. Alternatively orin combination, the outer portion 120 may comprise a rigidity sufficientto deflect when the eye blinks.

FIG. 1A3 shows a schematic illustration of the covering of FIGS. 1A1 and1A2 pumping tear liquid when the eye closes, in accordance withembodiments of the present invention.

When placed on the eye, the covering 100 can define a chamber with thelower surface of the covering extending along the cornea, the limbus andconjunctiva over the sclera. When the eyelids are separated, thecovering 100 is held loosely on the eye with slight pressure from theeyelids extending under the outer portion of the covering. When the eyeblinks, the lids extend over the outer portion 120 of the covering andinner portion 110 so as to exert pressure on the covering such that thecovering is urged downward toward the cornea and the volume of thechamber under the covering is decreased. The downward movement of theoptical component 100A of the inner portion 110 of the covering 100 canmove the covering downward so as to pass pumped tear liquid 100TLthrough the fenestrations, and in many embodiments the pumped tearliquid 100TL can pass under the peripheral portion 120P.

FIG. 1A4 shows a schematic illustration of the covering of FIGS. 1A1 and1A2 pumping tear liquid when the eye opens, in accordance withembodiments of the present invention.

When the eyelids open, the pressure on the covering is decreased, suchthat the covering can move away from the cornea and increase the volumeof the chamber. The movement of the optical portion 100A away from thecornea can draw pumped tear liquid 100TL into the covering through thefenestrations, and contact of the peripheral portion 120P and scleracoupling portion 130 with the conjunctiva can inhibit flow of tearliquid under the peripheral portion 120P. In many embodiments, theperipheral portion 120P and sclera coupling portion 130 can contact theconjunctiva so as to form a seal when the eyelids open and the opticalportion 100A moves away from the cornea.

The fenestrations 100F can be located away from the optical component,for example about 3.5 to about 4.5 mm from a center of the opticalcomponent to decrease optical artifacts of the fenestrations 100F.However, the fenestrations may be located within the optical componentwhen sufficiently small and diameter and sufficiently few so as to notproduce perceptible visual artifacts. The fenestrations may comprise apatter to indicate the orientation of the covering 100 on the cornea.For example the upper fenestration and lower fenestrations may indicateda 90 degree axis on the patient and horizontal fenestrations can beprovided to indicated the location of the 180 degree axis on thepatient. The fenestrations may comprise additional fenestrations to belocated inferiorly to indicate that the covering is not flipped by 180degrees on the patient, for example upside down. The additional inferiorfenestrations may also couple to the rivulet comprising tear liquid thatforms near the lower lid, so as to facilitate pumping of tear liquid.For example, when the eye blinks the lower lid may extend over theinferior fenestrations and the upper lid may extend downward to coupleto the lower rivulet. When the eye opens and the eyelids separate theupper eyelid can draw tear liquid of the rivulet over the upperfenestration and the lower eyelid can move inferiorly so as to pass therivulet over the inferior rivulets.

The covering 100 may comprise one or more of many optically clearmaterials, for example synthetic materials or natural material suchcollagen based materials, and combinations thereof, such as described inU.S. Pat. App. Ser. No. 12/384,659, filed Apr. 6, 2009, entitled“Therapeutic Device for Pain Management and Vision”, U.S. Pub. No. US2010-0036488 A1, published on 11 Feb. 2010. For example, the lensmaterial may comprise a naturally occurring material, such as collagenbased material. Alternatively or in combination, the lens material maycomprise a known synthetic material, for example hydroxyethylmethacrylate (HEMA) hydrogel, hydrogel, silicone, for example hydratedsilicone and derivatives thereof. For example the optically clearmaterial may comprise one or more of silicone, silicone hydrogel,silicone comprising resin, silicone comprising silicate, acrylate,collagen. The cured silicone may comprise silicone that is two-part heatcured and RTV (room temperature vulcanized). For example, polydimethylsiloxane such as NuSil, or poly(dimethyl) (diphenyl) siloxane may beused to mold the covering, for example with less than 10% water contentso as to increase oxygen diffusion through the covering. The covering100 may comprise perfluoropolyethers or fluorofocal. The lens materialcan be elastic, for example a stretchable elastic material such assilicone, such that the lens can seal the cornea. The lens material canbe cured with a hardness and size and shape such that the coveringcomprises a modulus within a range from about 4 to about 40 MPa. Thematerial may comprise, for example, silicone elastomer having opticallyclear silicate disposed therein and a water content of no more thanabout 10%, for example no more than about 5%, such that the lenscovering has a very high Dk exceeding 150, and the silicone lenscomprising silicate can be treated to provide a wettable surface. Thelens may comprise hydrogel, for example silicone hydrogel, and can beformed with a water content within a range from about 5% to about 35%and a modulus within a range from about 4 to about 40 MPa, such that thecovering conforms at least partially to the ablated stroma.

The covering may comprise silicone or silicone hydrogel having a lowionoporosity such that covering seals to the cornea. For example,covering may comprise silicone hydrogel comprising a low ionpermeability, and the range of water can be from about 5% to about 35%,such that the Dk is 100 or more. The low ion permeability may comprisean Ionoton Ion Permeability Coefficient of no more than about 0.25×10−3cm2/sec so as to seal the cornea, for example no more than about0.08×10−3 cm2/sec. The low ion permeability comprises an Ionoton IonPermeability Coefficient of no more than about 2.6×10−6 mm2/min to sealthe cornea, for example no more than about 1.5×10−6 mm2/min.

The covering 100 may comprise a wettable surface coating 134 disposed onat least the upper side of the covering, such that the tear film of thepatient is smooth over the covering and the patient can see. Thewettable surface coating may comprise a lubricious coating for patientcomfort, for example to lubricate the eye when the patient blinks. Thewettable coating may comprise a contact angle no more than about 80degrees. For example the coating may comprise a contact angle no morethan about 70 degrees, and the contact angle can be within a range fromabout 55 to 65 degrees to provide a surface with a smooth tear layer forvision. For example, the wettable coating can be disposed both an uppersurface and a lower surface of the covering. The upper surface maycomprise the wettable coating extending over at least the inner portion110.

The wettable coating 134 may comprise one or more of many materials. Forexample, the wettable coating 134 may comprise polyethylene glycol(PEG), and the PEG coating can be disposed on Parylene™. Alternatively,the wettable coating 134 may comprise a plasma coating, and the plasmacoating comprise a luminous chemical vapor deposition (LCVD) film. Forexample, the plasma coating comprises at least one of a hydrocarbon, forexample CH4, O2 or fluorine containing hydrocarbon, for example CF4coating. Alternatively or in combination, the wettable coating maycomprise a polyethylene glycol (PEG) coating or2-hydroxyethylmethacrylate (HEMA). For example, the wettable coating maycomprise HEMA disposed on a Parylene™ coating, or the wettable coatingmay comprise N-vinylpyrrolidone (NVP) disposed on a Parylene™ coating.

The covering 100 may comprise a base radius R1 of curvaturecorresponding to a curvature of a central portion of the cornea. Thecovering 100 comprises a first configuration 100C1 when placed on thecornea and the eyelids are spaced apart and a second configuration 100C2when placed on the cornea and the blinks such that the eyelids. Thefirst configuration 100C1 and the second configuration 100C2 pump tearliquid under the covering 100.

The covering 100 may comprise a lower surface corresponding to one ormore of many suitable shapes to fit the covering to the cornea, such asa natural unablated cornea or an ablated cornea following refractivesurgery such as PRK. The lower surface of the inner portion 110 of thecovering 100 may correspond to base radius of curvature. With postablation corneas, the covering can resist deformation and smooth theepithelium over about 3 mm and may deflect so as conform substantiallyto the ablated cornea over a larger dimension such as 6 mm. The coveringmay comprise a second curve in combination with a first curve, such thatthe lower surface comprises a bicurve surface. Alternatively, the lowersurface may correspond to an aspheric surface. For example an asphericsurface may comprise an oblate shape and conic constant to fit a postPRK eye. The curved and aspheric surfaces as described herein can fitnon-ablated eyes and the covering can be selected by based on thecurvature of an unablated central region of the cornea. Also, it may behelpful to identity a covering that fits the cornea, for example withselection of one covering from a plurality of sizes.

The covering 100 may comprise an inner portion 110 having an opticalcomponent 1 100A. The optical component 100A may comprise an innerportion 110 of the covering 100. The optical component may have amodulus within a range from about 5 MPa to about 40 MPa, and a thicknesswithin a range from about 100 μm to about 300 μm such that centralportion can have sufficient rigidity to resist deformation and smoothirregularities and correct vision. The covering may comprise anelastomeric stretchable material such that the covering can stretch tofit the cornea, for example. The covering having the modulus within arange from about 4 MPa to about 40 MPa can be formed in many ways asdescribed herein. For example, the covering may comprise a single pieceof material having a non-uniform thickness extending across the cornea.The covering can be shaped in many ways and may comprise a single pieceof one material, or may comprise a single piece composed to two similarmaterials, or may comprise a plurality of materials joined together.

FIG. 1B1 shows covering 100 having a tricurve profile to fit sclera andcornea. The tricurve profile can be used to fit an unablated naturaleye, in which the base curvature R1 corresponds to the optically usedcentral portion of the cornea. For ablated corneas, the base curvatureR1 may correspond to the ablated cornea. The tricurve covering maycomprise an inner portion with an inner lower surface having radius ofcurvature R1 and an outer portion comprising an outer lower surfacehaving radius of curvature R1B. The outer portion 130 may comprise thesclera coupling portion 130 having a third radius of curvature R1C sizedto fit the conjunctiva located over the sclera and contact theconjunctiva so as to inhibit sliding movement of inner portion 110. Workin relation to embodiments suggests that coupling to the sclera mayimprove alignment of the lens on the cornea.

The covering 100 having the tricurve profile may comprise dimensionssized to fit the cornea and sclera of the eye 2. The covering 100 havingthe at least tricurve profile may comprise an inner portion 110 and anouter portion 120 as described herein. The outer portion 120 maycomprise the third sclera coupling portion 130 having curvature R1Cshaped to fit the sclera of the eye, for example shaped so as to contactthe conjunctiva of the eye such that the conjunctiva is located betweenthe sclera and the sclera coupling portion 130. The inner portion 110may comprise a dimension 102 and the outer portion 120 may comprise adimension 104 as described herein. The covering 100 may comprise a sagheight 105 extending between an upper location of the inner portion 110and the outer boundary of outer portion 120 shaped to fit the cornea.The sclera coupling portion 130 may comprise a dimension across 103.

The dimension 102, the dimension 104, the dimension 103, the dimension105 and the dimension 105S can be sized to the eye based on measurementsof the eye. The dimension 103 may correspond to an annular region of thesclera extending from the limbus to the outer boundary of the scleracoupling portion across a distance within a range from about 1 to 4 mm,for example within a range from about 1.5 to 2 mm. The size of thelimbus of the eye can be measured so as to correspond to dimension 104,for example, and can be within a range from about 11 to 13 mm. Thedimension 105 may correspond to a height of the eye from the vertex ofthe cornea to the limbus, and the dimension 105S may correspond to thesag height were the outer location of the covering couples to theconjunctiva covering the sclera.

The dimension 102 may correspond to an inner region of the naturalcornea or the dimension across an ablation. Dimension 102 may correspondto the more rigid inner portion 110 can be sized about 0.5 to about 2 mmless than the dimension across the ablation zone, such that the soft andless rigid outer portion 120 contacts the eye near the edge of theablation and the epithelial debridement.

The radius of curvature R1C of portion 130 can be determined so as tofit the eye, and can be within a range from about 12 mm+/−3 mm. Theradius R1B of the outer portion can be fit to within about +/−0.5 mm,for example to within about +/−0.25 mm.

The dimensions of the covering 100 can be determined in many ways, forexample with topography measurements of the cornea and sclera. Thecorneal and scleral topography can be measured with many instruments,such as with the Orbscan™ topography system commercially available fromBausch and Lomb, and the Pentacam™ Scheimpflug camera systemcommercially available from Oculus, and commercially available opticalcoherence tomography (OCT). The ablation profile can be combined withthe topography to determine the shape of the eye.

The dimensions of covering 100 can be sized to one or more of the corneaand sclera based on tolerances that may be determined clinically.

The outer portion 120 and sclera coupling portion 130 may comprise ahydrogel material, for example a silicone hydrogel material, and theinner portion 110 may comprise the rigid material 110M, for examplesecond layer 110L2 and second material 110M2 between first layer 110L1of first material 110M1 and third layer 110L3 of third material 110M3 asdescribed herein.

The portions of the coverings as described herein, for example the innerportion and the outer portion, may comprise a junction wherein a firstportion connects with a second portion, and the junction may have themodulus as described herein. The covering may comprise a contact lenshaving a central lens portion having a center stiffness of at leastabout 2 psi*mm2 coupled to an outer lenticular junction portion having alenticular junction stiffness of at least about 5 psi*mm2.

FIG. 1B2 shows covering 100 having a tricurve profile to fit sclera withslopes of the curved profiles aligned so as to inhibit ridges at theboundaries of the curved portions, in accordance with embodiments of thepresent invention. The inner portion 110 comprises the optical component100A and the outer portion 120 comprises the coupling component 100B.The coupling component 100B may comprise a thin layer of material 120Mextending under the optical component 100A for improved comfort andsupport of the optical component. The outer portion 120 comprisingcoupling component 100B may comprise fenestrations 100F as describedherein. The inner portion 120 comprises first radius R1 along the lowersurface and a first anterior radius R1A along the upper surface. Theouter portion 120 couples to the inner portion with a second radius R1Baligned with the first radius R1A at a boundary corresponding todimension 102. The outer portion 120 has a second anterior radius R1BAextending along the anterior surface. The outer portion 120 comprisingsecond radius R1B along the lower surface to contact the cornea maycouple to sclera coupling portion 130 at a location corresponding to thelimbus of the eye, for example along a boundary corresponding todimension 104. Work in relation to embodiments suggests that formationof a ridge near the boundary of the cornea contacting portion and scleracoupling portion may decrease epithelial cell migration somewhat morethan would be ideal, and the alignment of the curved profiles to inhibitridge formation can provide a smooth transition over the limbus and maydecrease mechanical pressure to the limbus. The sclera contactingportion 130 comprises an upper surface having an anterior radius ofcurvature R1CA.

The inner portion 110 can be curved to fit an ablated eye or anon-ablated eye. The modulus and thickness of the sclera couplingportion can be configured in many ways to fit may eyes with comfort andso as to resist movement of the inner portion 120. The modulus of scleracoupling portion 130 may be no more than about 5 MPa and the thicknessno more than about 200 μm, for example no more than 100 μm, so as tostretch substantially for comfort and resist movement of the innerportion when the placed on the sclera.

The dimension 103 of sclera coupling portion 130 may correspond to anannular region of the sclera extending from the limbus to the outerboundary of the sclera coupling portion across a distance within a rangefrom about 1 to 4 mm, such that the dimension 103 can be from about 12mm to about 16 mm, for example from about 14 mm to about 16 mm.

The radius of curvature R1C, thickness and modulus of the portion 130can be configured so as to fit the eye to resist movement of innerportion 110 and with comfort. The radius of curvature R1C can be sizedless than the radius of curvature of the sclera and conjunctiva. Forexample, the radius of curvature R1C can be no more than about 10 mm,for example no more than about 9 mm when the curvature of the scleraportion of the eye is at least about 12 mm for example. The thirdrelative rigidity may comprise no more than about 4E-5 Pa*m{circumflexover ( )}3 so as to stretch substantially for comfort and resistmovement of the inner portion when the outer portion is placed on thesclera.

The thickness of the sclera coupling portion having radius of curvatureR1C can vary, for example from a thickness of about 100 μm to a taperededge.

FIG. 1B2-1 shows alignment of the slope of the lower surface of thecorneal contacting portion comprising second radius R1B with the slopeof the lower surface of the sclera coupling portion 130 comprisingradius R1C, such that pressure to the limbus is decreased substantially.The second slope corresponding to second radius R1B is given by a heightR1BY and a length R1BX, and the third slope corresponding to thirdradius R1C is given by height R1CY and width R1CX. The second slope isaligned with the third slope such that no substantial ridge is formed atthe location corresponding to the limbus. For example, the first slopecan be substantially equal to the second slope. The slope of the innerportion 110 can be aligned with the slope of the second portion 120 at alocation corresponding to dimension 102 in a similar manner.

FIG. 1B3 shows a tapered edge of the covering of FIG. 1B1 having atricurve profile to fit sclera and cornea. The sclera coupling portion130 may comprise a flange 120F having a narrowing taper extending adistance 120FW to a chamfer 120FE. The chamfer 120FE can be definedalong an outer rim where a first convexly curved lower surface joins asecond convexly curved upper surface. The convex surfaces along theouter rim allow the covering to slide along the conjunctiva and thenarrowing taper permits the sclera coupling portion of the covering tostretch substantially and couple to the sclera and conjunctiva withdecreased resistance for comfort.

The dimensions of the covering 100 can be determined in many ways, forexample with one or more topography measurements or tomographymeasurements of the cornea and sclera. The corneal and sclera topographycan be measured with many instruments, such as with the Orbscan™topography system commercially available from Bausch and Lomb, and thePentacam™ Scheimpflug camera system commercially available from Oculus.The tomography can be measured with optical coherence tomography(hereinafter “OCT”) so as to determine the sag height of the limbus andconjunctiva, for example with OCT measurement systems commerciallyavailable from Zeiss/Humphrey. The ablation profile can be combined withthe topography to determine the shape of the eye.

FIG. 1B4 shows a plan view covering 100 having a multi-curve profile tofit the cornea, limbus and sclera with slopes of the curved profilesaligned so as to inhibit ridges at the boundaries of the curvedportions, in accordance with embodiments of the present invention. Thecovering 100 comprises fenestrations 100F and optical component 100A forvision correction and outer coupling component 100B that may pump tearliquid as described herein.

FIG. 1B5 shows a side sectional view of the covering of FIG. 1B4 andcorresponding curved portions to couple to the cornea, limbus andsclera, in accordance with embodiments of the present invention.

The inner portion 110 comprises optical component 100A, which maycomprise material 110M. The outer portion 120 comprises couplingcomponent 100B, which may comprise outer material 120M. The innerportion 110 is coupled to the outer portion along a boundarycorresponding to dimension 102. The lower surface of inner portion 110has a shape profile corresponding to a first radius R1. The outerportion 120 couples to the inner portion with a first outer radius R1B1of curvature, such that the slopes are aligned as described herein at alocation corresponding to dimension 102. The outer portion 120 comprisesa second outer radius R1B2 of curvature coupled to the first outerradius of curvature R1B1. The first outer radius R1B1 of curvature iscoupled to the second outer radius R1B2 of curvature with the slopesaligned as described herein at a location corresponding to dimension104A. The outer portion 120 comprises a third outer radius R1B3 ofcurvature coupled to the second outer radius of curvature R1B2. Thesecond outer radius R1B2 of curvature is coupled to the third outerradius R1B3 of curvature with the slopes aligned as described herein ata location corresponding to dimension 104B.

The first outer radius of curvature R1B1, the second outer radius ofcurvature R1B2, and the third outer radius of curvature R1B3 maycomprise values determined from a patient population. The first radiusof curvature R1 may comprise a value determined based on the patientpopulation. Alternatively or in combination, the first radius ofcurvature R1 may correspond to a post ablation profile.

The first outer radius of curvature R1B1, the second outer radius ofcurvature R1B2, and the third outer radius of curvature R1B3 can becombined or replaced with an aspheric surface such as a conic surface.The conic surface can be determined in accordance with first outerradius of curvature R1B1, the second outer radius of curvature R1B2, andthe third outer radius of curvature R1B3, such that the conic surfacecorresponds to values determined from a patient population.

The sclera coupling portion 130 may have a lower surface comprising afirst sclera coupling radius R1C1 of curvature and a second scleracoupling portion having a second sclera coupling radius R1C2 ofcurvature. The first sclera coupling portion comprising radius R1C1 canbe aligned to the third radius R1B3 at a location corresponding todimension 104. The second sclera coupling portion comprising radius R1C2can be aligned to the first sclera coupling portion having radius R1C1at a location corresponding to dimension 120FW corresponding to an innerboundary of tapering flange 120F.

FIG. 1B6 shows a side sectional view of the covering of FIG. 1B4 andcorresponding curved portions of the upper surface, in accordance withembodiments of the present invention. The upper surface may comprise aninner anterior radius of curvature R1A, a first outer anterior radius ofcurvature R1B1A, a second outer anterior radius of curvature R1B2A. Thesclera coupling portion 130 may comprise a first anterior radius R1C1Aof curvature and a second anterior coupling radius R1C2A of curvature.

FIG. 1B7 shows a tapered edge of the covering of FIG. 1B4, in accordancewith embodiments of the present invention.

FIG. 1C shows therapeutic covering 100 comprising a covering molded witha homogeneous material, in which the outer portion comprises a thicknessconfigured to conform with the cornea and in which the inner portion 110comprises thickness configured to smooth the epithelium and cornea. Theinner portion 110 comprises optical component 100A, and the outerportion 120 comprises coupling component 100B. The inner portion 110 maycomprise a thickness of no more than about 300 microns, for example nomore than about 200 microns. Many materials can be used as describedherein, and the covering may comprise one or more materials. Forexample, the covering may comprise a single piece of material such assilicone having a water content within a range from about 0.1% to about10%, for example no more than about 1%, and a hardness Shore A durometerparameter within a range from about 5 to about 90, for example within arange from about 40 to about 85.

FIG. 1C1 shows a covering 100 having an inner portion 110 comprising aninner thickness and an inner material 110M and an outer portion 120comprising an outer thickness and an outer material 120M, in which theinner thickness is greater than the outer thickness. The inner material110M may comprise many materials and may comprise an optically clearsilicone, for example silicone with resin. The inner material maycomprise silicone positioned in a mold with the outer portion 120 formedaround the inner portion. The inner portion may comprise a hardnesssimilar to the outer portion. The outer material 120M of the outerportion 120 may comprise a material similar to the inner portion. Forexample the outer material 120M may comprise silicone and the innermaterial 110M may comprise silicone. This use of similar materials onthe inner and outer portion can improve adhesion of the inner portion tothe outer portion. The outer material 120M may extend along the innerportion 110, for example along the underside of the inner portion 110,such that the inner material 110M is held in a pocket of the outermaterial 120M. Alternatively, the inner material 110M may extendsubstantially across the thickness of the inner portion 110, such thatthe outer material 120M comprises a substantially annular shape with theinner material 110M comprising a disc shaped portion disposed within theannulus and extending substantially from the upper surface coating tothe lower surface coating when present.

FIG. 1C2 shows covering 100 having inner portion 110 comprising an innerthickness and inner material 110M and outer portion 120 comprising anouter thickness and outer material 120M, in which the inner thicknesscan be greater than the outer thickness and the outer material 120Mextends around the inner material 110M. The inner portion 110 comprisesthe optical component 100A and the outer portion 120 comprises thecoupling component 100B. The covering 100 may comprise at least abicurve covering having at least a second radius R1B. The inner portion110M may comprise three layers of material, a first layer 110L1 of afirst material 110M1, a second layer 110L2 of a second material 110M2and a third layer 110L3 of a third material 110M3. The second material110M2 may comprise a rigid material, for example one or more of a rigidgas permeable material, a rigid silicone, or a rigid silicon acrylate.The first material 110M1 and the third material 110M3 may comprise asoft material, for example a soft elastomer or soft hydrogel such as oneor more of a soft optically clear silicone or a soft silicone hydrogel.The first material, the third material, and the outer material 120M maycomprise similar materials, such that the second layer of rigid material110M2 is encapsulated with the first soft material 110M1, the third softmaterial 110M3 and on the perimeter with the soft outer material 120M.In many embodiments, the second rigid material 110M2 comprises amaterial similar to each of the first material 110M1, the third material110M3 and the outer material 120M, for example each may comprisesilicone, such that the corresponding portions of the covering 100 canbe bonded together with the silicone similar silicone elastomermaterial, for example. In many embodiments, the covering 100 can beformed in a mold with rigid second material 110M2 placed in the mold andencapsulated within a single piece of material comprising first material110M1, third material 110M3 and outer material 120M, such that firstmaterial 110M1, third material 110M3 and outer material 120M comprisesubstantially the same material, for example silicone elastomer. Therigid second material 110M2 may comprise silicone bonded to each offirst material 110M1, third material 110M3 and the outer material 120M,for example with curing such that first material 110M1, third material110M3 and outer material 120M comprise the same soft silicone materialbonded to the second material 110M2 comprising rigid silicone.

The soft material comprising soft outer portion 120 composed of softmaterial 120M, first layer 110L1 composed of soft material 110M1 andthird layer 110L3 composed of soft material 120M3 can provide improvedcomfort and healing for the patient, and can extend the amount of timethe covering can be worn in the eye when combined with the fenestrations100F and sclera coupling component 130 and peripheral portion 120P andflange 120F as described herein. The soft material can deflect, bend orindent so as to conform at least partially to the tissue of the eye whenthe rigid portion comprising rigid material 110M2 corrects vision of thepatient. The dimension 102 across inner portion 110 can be sized tosubstantially cover one or more of the entrance pupil of the eye orablation zone. With ablated eyes, the dimension 102 can be sizedslightly smaller than the ablation dimensions, such as ablation diameter20D, so that the epithelium can grow inward and contact the layer 110L1of soft first material 110M1 without substantial disruption from therigid material 120M2 when the inner portion 110M corrects vision withthe layer of rigid material 110M2. The eyelid can also move over thethird layer 110M3 for improved comfort. The soft first material 110M1and soft third material 110M3 may comprise soft elastomer or softhydrogel, for example, and may each comprise the same material so as toencapsulate the second layer 110L2 of rigid second material 110M2.

The soft material comprising soft outer portion 120 composed of softmaterial 120M, first layer 110L1 composed of soft material 110M1 andthird layer 110L3 composed of soft material 120M3 can have a moduluswithin a range from about 1 to 20 MPa, for example within a range fromabout 1 to 5 MPa.

The material inner material 120M and 120M2 of second layer 120L2 canhave a modulus within a range from about 5 to about 35 or more, forexample as set forth in Table A below. For example, when material 120Mcomprises silicone elastomer or layer 110L2 of material 120M2 comprisessilicone elastomer, the modulus can be within a range from about 5 toabout 35 MPa, for example within a range from about 20 to about 35 MPa.

The layers of covering 100 can comprise dimensions so as to providetherapeutic benefit when placed on eye 2. The thickness of layer 110L1can be from about 5 μm to about 50 μm, for example, within a range fromabout 10-30 μm, such that the layer 110L1 can provide a soft at leastpartially conformable material to receive the lens. The middle layer110L2 can be from about 20 μm to about 150 μm, for example, and materialM2 can have a modulus greater than first material 110M1 of first layer110L1, so as to deflect the epithelium of the eye when the middle layeris deflected. The third layer 110L3 can be within a range from about 5μm to 50 μm, for example within a range from about 10 μm to about 30 μm,and can cover second layer 110L2 so as to retain the second layer in theinner portion 110 of the covering 100.

The therapeutic covering 100 may comprise a first inner material 110Mand a second outer material 120M, in which the outer portion 120comprises a hardness configured to stretch elastically and conform withone or more of epithelium of the cornea or the conjunctiva, and in whichthe inner portion 110 comprises second hardness configured to smooth thecornea to provide optical benefit. The outer material 120M may comprisemany materials as herein. The Shore A hardness of each of the innerportion and the outer portion can be within a range from about 5 toabout 90. For example, the outer material 120M may comprise siliconehaving a hardness Shore A durometer parameter from about 20 to about 50,for example from about 20 to about 40, and the inner material 110M maycomprise silicone having a hardness durometer parameter from about 40 toabout 90, for example from about 50 to about 90. The outer portioncomprises a perimeter 120P, and the perimeter may comprise a peripheraland circumferential edge structure to abut the epithelium to form theseal with the epithelium, for example when the base radius of thecovering is less than the cornea. The peripheral and circumferentialedge structure can be shaped in many ways to define an edge extendingaround the perimeter to abut the epithelium, for example with one ormore of a taper of the edge portion extending to the perimeter, a bevelof the edge portion extending to the perimeter or a chamfer of the edgeportion extending to the perimeter. The inner portion 110 may compriseinner thickness and inner material 110M and the outer portion 120 maycomprise an outer thickness and outer material 120M, in which the innerthickness is substantially similar to the outer thickness.

The peripheral edge structure to abut the epithelium can be used withmany configurations of the inner portion as described herein. Forexample, the inner portion may comprise an RGP lens material having alower rigid surface to contact and smooth the cornea and an upper rigidoptical surface. Alternatively, the inner portion may conform to thecornea as described herein. The outer portion may comprise a skirt, andthe skirt may comprise the peripheral edge structure to abut and sealthe cornea, such as the chamfer. The rigidity of the outer portioncomprising the edge structure can be determined to seal the cornea withone or more of hardness and thickness, as described herein.

FIG. 1C2A shows a covering as in one or more of FIGS. 1-2A to 1B7 havinga layer of hydrogel material on a posterior surface of the covering. Thecovering 100 may comprise a wettable surface coating 134 disposed on atleast the upper side of the covering as described herein. The layer ofhydrogel material may comprise an inner portion of the layer of hydrogelmaterial 110MHG and an outer portion of the layer of hydrogel material120MHG. The layer of hydrogel material extends to the fenestration so asto couple the hydrogel material to the fenestration. The hydrogelmaterial can be coupled to the fenestration in many ways. For example,the layer of hydrogel material may cover the fenestration, or thefenestration 100F may extend through the hydrogel material. Thefenestration 100F extending through the layer of hydrogel material canencourage pumping of the tear liquid as described herein. Alternativelyor in combination, the layer of hydrogel material covering a posteriorsurface of the fenestration 100F to couple the fenestration 100F to thehydrogel layer may encourage movement of a therapeutic agent along thehydrogel layer toward a central portion of the cornea for example. Thehydrogel may extend along a deflectable portion of the covering so as toexert at least some pressure on the hydrogel layer to encourage movementof one or more of tear liquid or the therapeutic agent along thehydrogel layer when the patient blinks, for example.

The hydrogel layer as described herein may encourage regeneration of theepithelium and may provide a soft surface to contact the epitheliumregenerating over the ablation so as to encourage epithelialregeneration under the optical component as described herein, and theoptical component can resist deformation so as to protect the epitheliumand provide an environment to encourage regeneration of the epithelium.

The hydrogel material may comprise one or more of the hydrogel materialsas described herein. The hydrogel material extending along the lowersurface can increase comfort of the covering when placed on the eye. Thehydrogel material may comprise a substantially uniform thickness withina range from about 1 μm to about 100 μm, for example from about 2 μm toabout 50 μm and in many embodiments within a range from about 5 μm toabout 20 μm. The hydrogel material extending along the posterior surfacemay comprise on or more of the hydrogel materials as described hereincombined with one or more of materials 110M, 110M1, 110M2, 110M3 or 120Mas described herein. For example the one or more of materials 110M,110M1, 110M2, 110M3 or 120M may comprise silicone such as siliconeelastomer comprising siloxane, and the hydrogel may comprise a hydrogelsuch as silicone hydrogel material as described herein.

FIG. 1C2B shows a covering as in one or more of FIGS. 1-2A to 1B7 havinga layer of hydrogel material on a posterior surface of the coveringextending less than a maximum distance across the covering such that endportions of the covering are configured to engage the epithelium of theeye away from the hydrogel layer and inhibit movement of the coveringwhen placed on the eye. In many embodiments, the material 120M cancouple to the surface of the eye, for example the epithelium so as toinhibit movement of the covering. The material 120M may comprise asticky tacky hydrophobic material such as silicone to engage theepithelium to inhibit movement, and the material 120M may be coated withone or more coatings as described herein, for example with vapordeposition. The hydrogel material can be coupled to the fenestration inmany ways. For example, the layer of hydrogel material may cover thefenestration, or the fenestration 100F may extend through the hydrogelmaterial.

FIG. 1C2C shows a covering 100 as in one or more of FIGS. 1-2A to 1B7having an annular layer of hydrogel material 120MHG on a posteriorsurface of the covering such that an inner portion of the coveringcontacts the cornea away from the hydrogel layer and an outer portion ofthe covering contacts the cornea away from the covering when placed onthe eye. Work in relation to embodiments suggests that the annularhydrogel layer can provide an environment to encourage growth of theepithelium along the posterior surface of inner material 110M1 asdescribed herein, and the lower surface of material 110M1 can be coatedwith a material having a thickness less than the hydrogel, for example.

FIG. 1C3 shows a covering having a tricurve profile to fit sclera withslopes of the curved profiles aligned so as to inhibit ridges at theboundaries of the curved portions as in FIG. 1B2 and having a layer ofhydrogel material 120MHG on a lower surface. The hydrogel material 120Mmay extend substantially across the posterior surface of the covering.The covering may extend along the lower surface a distance less than adistance across the covering so as to provide a portion of the coveringwithout the hydrogel to engage the eye, for example the epithelium ofthe eye that may comprise one or more of the corneal epithelium or theconjunctival epithelium. Alternatively, the covering may extendsubstantially along the posterior surface of the covering correspondingto the distance across the covering so as to provide the hydrogelcovering over the outer portion of the covering that engages the eye.

FIG. 1C4 shows a plan view covering having a tricurve profile to fit thecornea, limbus and sclera with slopes of the curved profiles aligned soas to inhibit ridges at the boundaries of the curved portions as in FIG.1B4 and having a hydrogel material on a lower surface extending lessthan a maximum distance across the covering to engage the conjunctivawith the covering away from the hydrogel material. Alternatively, thecovering may extend substantially along the posterior surface of thecovering corresponding to the distance across the covering so as toprovide the hydrogel covering over the outer portion of the coveringthat engages the eye. The hydrogel covering may comprise an annularshape extending along the lower surface as described herein.

FIG. 1C5 shows a fenestration 100F having a posterior end 100FPE coveredwith a layer of hydrogel material 29MHG extending along the posteriorsurface of the covering 100, in accordance with embodiments of thepresent invention.

FIG. 1C6 shows a fenestration 100F extending through a layer of hydrogelmaterial 120MHG extending along the posterior surface of the covering100, in accordance with embodiments of the present invention.

FIG. 1D shows a covering comprising channels 100FC extending radiallyoutward from fenestrations 100F along a lower surface of the covering,in accordance with embodiments.

FIG. 1E shows a covering comprising 100FC channels extending radiallyinward from fenestrations 100F along a lower surface of the covering, inaccordance with embodiments.

FIG. 1F shows a test apparatus 190 to measure deflection of a portion ofa lens in response to a load. The load deflection of the coverings andcomposite layers as described herein can be used to determine thedeflection of the covering and corresponding pumping. Work in relationto embodiments suggests that one or more of the inner covering or theouter covering contacting the epithelium may comprise a rigidity suchthat blinking of the eye deflects the covering sufficiently with elasticdeformation so as to urge tear liquid from beneath the covering asdescribed herein. For example, the inner portion 120 of the coveringssuited to cover the ablated cornea and provide pumping as describedherein are also well suited to cover natural unablated corneas toprovide vision correction with pumping of the tear liquid. The outerportion 120 may comprise a rigidity as described herein sufficient todeflect when the eye blinks and provide elastic deformation that maypump tear liquid under the covering such as a contact lens.

The test apparatus 190 may comprise a rigid support having an aperture192, such that deflection of the covering 100 through the aperture 192can be measured. The aperture 192 has a dimension across 194 that can besized smaller than the dimension across inner portion 110, so as tomeasure a deflection 110D of the inner portion 110 in response to a load196. The deflection 110D may comprise a peak deflection, for example adistance. The load 196 may comprise a point load or a load distributedover an area corresponding to diameter 104, for example a pressure froma gas or liquid on the lower side of the covering. The covering maycomprise a first configuration C1 corresponding to the shape of thecovering prior to placement on the eye, and the covering may comprise asecond configuration C2 when placed on the eye, and the amounts of forceand/or pressure to deflect covering 100 can be determined such thatcovering 100 can be deflected without substantially degrading vision andso as to smooth the epithelium. For example, the covering may deflectslightly so as to decrease vision no more than about 1 or 2 lines ofvisual acuity and such that the covering can smooth the epithelium andprovide environment 100E as described herein.

The modulus and thickness of the covering can be used to determine anamount of relative rigidity of the covering 100, the correspondingamount of force to deflect the covering 100 across a distance, and thecorresponding amount pressure to smooth the epithelium with thedeflected covering as described herein.

The amount of relative rigidity can be determined based on the modulusmultiplied with cube of the thickness. The amount of deflectioncorresponds to the 6^(th) power of the deflected span across thecovering, the modulus, and the cube of the thickness. The approximatelyfourth order relationship of the span to the deflection can allow thecoverings as described herein to conform at least partially to theablation profile within a range from about 4 to 6 mm, and inhibitsubstantially irregularities having diameters of about 3 mm or less, forexample.

The deflection can be approximated with the following equation:

Deflection≈(constant)*(Load*Span{circumflex over( )}4)/(Modulus*thickness{circumflex over ( )}3)

The above approximation can be useful to understand the properties ofcovering 100, for example with a substantially uniform thickness of theinner portion. The substantially uniform thickness may comprise athickness that is uniform to within about +/−25%, for example to withinabout +/−10%, such that the covering can conform substantially to atleast a majority of the surface area of an ablation zone and inhibitirregularities over a smaller portion of the ablation zone correspondingto no more than a minority of the surface area of the ablation. In manyembodiments, the covering conforms over an area having diameter of atleast about 4 mm and inhibits irregularities over an area having adiameter of no more than about 4 mm, for example less inhibitsirregularities over an area of no more than about 3 mm. For example,based on the above equations, the deflection is related to the fourthpower of the span, such that for a comparable load, a 2 mm span willhave about 1/16^(th) the deflection of a 4 mm span. Similarly, a 3 mmspan will have a deflection that is about 1/16^(th) the deflection of a6 mm span. As the deflection is related to the cube of the thickness,doubling the thickness can decrease the deflection by about a factor of8. The above approximations can be combined with clinical testing todetermine thicknesses and moduli suitable for incorporation inaccordance with embodiments as described herein.

The equations for deflection of an unsupported circular span of amaterial having a substantially uniform thickness are:

$E_{c} = {{E_{1}\left( \frac{t_{1}}{t_{1} + t_{2}} \right)} + {E_{2}\left( \frac{t_{2}}{t_{1} + t_{2}} \right)}}$"Relative"  Rigidity = E_(c)(t₁ + t₂)³$y = {\frac{3\; w\; R^{4}}{16\; {Et}^{3}}\left( {5 + v} \right)\left( {1 - v} \right)}$$w = \frac{y\; 16\; {Et}^{3}}{\left( {5 + v} \right)\left( {1 - v} \right)3\; R^{4}}$

where:

W=evenly distributed load over the surface, Pressure (Pa)

R=span of unsupported material (m)

E=Young's Modulus (Pa)

t=Thickness (m)

v=Poisson's Ratio (unit-less, assumed to be constant among materials)

y=Deflection (m)

Equation for deflection is described in Theory and analysis of elasticplates, Junuthula Narasimha Reddy, p. 201 equation 5.3.43 (1999).

Although the above equations describe relative rigidity for asubstantially flat surface, the equations can approximate a curvedsurface and a person of ordinary skill in the art can determine thedeflection load and relative rigidity empirically based on the teachingsdescribed herein, for example with finite element modeling.

TABLE A1 Material, modulus, thickness, relative rigidity Dk/anddeflection load of inner portions of coverings as described herein.Uniform Button Button Flexural Flexural Relative Button ThicknessThickness Modulus Modulus Rigidity Material Material (um) (m) (MPa) (Pa)(Pa*m{circumflex over ( )}3) Dk Dk/t Rigid 250 2.50.E−04 35 350000005.47E−04 600 240 Silicone Rigid 200 2.00.E−04 35 35000000 2.80E−04 600300 Silicone Rigid 150 1.50.E−04 35 35000000 1.18E−04 600 400 SiliconeRigid 100 1.00.E−04 35 35000000 3.50E−05 600 600 Silicone Rigid 505.00.E−05 35 35000000 4.38E−06 600 1200 Silicone Exemplary 293 2.93.E−0420 20000000 5.03E−04 600 205 Silicone Exemplary 272 2.72.E−04 2020000000 4.02E−04 600 221 Silicone Exemplary 250 2.50.E−04 20 200000003.13E−04 600 240 Silicone Exemplary 215 2.15.E−04 20 20000000 1.99E−04600 279 Silicone Exemplary 200 2.00.E−04 20 20000000 1.60E−04 600 300Silicone Exemplary 175 1.75.E−04 20 20000000 1.07E−04 600 343 SiliconeExemplary 150 1.50.E−04 20 20000000 6.75E−05 600 400 Silicone Exemplary100 1.00.E−04 20 20000000 2.00E−05 600 600 Silicone Exemplary 505.00.E−05 20 20000000 2.50E−06 600 1200 Material enflufocon 25 2.50.E−051900 1900000000 2.97E−05 18 72 A (Boston ES) enflufocon 50 5.00.E−051900 1900000000 2.38E−04 18 36 A enflufocon 150 1.50.E−04 19001900000000 6.41E−03 18 12 A hexafocon 25 2.50.E−05 1160 11600000001.81E−05 141 564 B (Boston XO2) hexafocon 50 5.00.E−05 1160 11600000001.45E−04 141 282 B hexafocon 150 1.50.E−04 1160 1160000000 3.92E−03 14194 B

As shown in Table A1, an RGP material such as an enflufocon or hexafoconhaving a thickness of about 50 μm can have a relative rigidity suitablefor epithelial smoothing and so as to conform at least partially to theablated stroma. The rigid silicone having a modulus of about 20 MPa anda thickness of about 250 μm will provide a relative rigidity 3E-4 anddeflection under load similar to the RGP material having a thickness ofabout 50 μm and modulus of about 1900 MPa so as to provide a relativerigidity of about 2.4E-4. Commercially available RGP lens materials asshown in Table A1 can be combined in accordance with embodiments asdescribed herein so as to provide covering 100. Based on the teachingsdescribed herein, a person of ordinary skill in the art can determinethe thickness of the covering based on the modulus and the intendedrelative rigidity.

Work in relation to embodiments in accordance with clinical studies asdescribed herein has shown that the inner portion 110 of the covering100 having the relative rigidity of about 3E-4 (3×10⁻⁴ Pa*m{circumflexover ( )}3) can be effective so to improve vision and conform at leastpartially of the eye so as to provide at least some comfort and improvefitting. Many eyes have been measured with many coverings and work inrelation to embodiments indicates that an inner portion 110 having arelative rigidity within a range from about 1E-4 to about 5E-4(Pa*m{circumflex over ( )}3) can allow the covering to conform to theablation and smooth the epithelium as described herein. For example,inner portion 110 may a relative rigidity within a range from about 2E-4to about 4E-4, and the eye can be fit accordingly based on thedeflection of the covering 100.

The relative rigidity can be related to the amount of deflection of thecovering 100 on the eye. Work in relation to embodiments indicates thata relative rigidity of inner portion 110 about 3E-4 can deflect about+/−2D when placed on the eye so as to conform to an ablation to withinabout +/−2D across the approximately 5 or 6 mm ablation diameter when aninner diameter of about 2 or 3 mm is smoothed. A covering 100 having arelative rigidity of about 1.5 E-4 can deflect about +/−4D when placedon the eye so as to conform to an ablation to within about +/−4D acrossan approximately 5 or 6 mm diameter when an inner diameter of about 2 or3 mm is smoothed.

The outer portion of the covering may comprise a relatively rigidityless than the inner portion to fit an outer portion of the eye such asan outer portion of the cornea or to fit the sclera when placed on theconjunctiva.

The coverings as described herein may comprise a relative rigiditycorresponding to a range within two or more values of many of thecoverings of Table A1, for example a relative rigidity within a rangefrom about 2.50E-06 to about 6.41E-03(Pa*m{circumflex over ( )}3), andtwo or more intermediate values for example within a range from about6.75E-05 to about 5.47E-04(Pa*m{circumflex over ( )}3). Based on theteachings described herein the covering can have a relative rigiditywithin one or more of many ranges such as within a range from about 0.5E-3 to about 10 E-3 (Pa*m{circumflex over ( )}3), for example a rangefrom about 1 E-3 to about 6 E-3, for example. Based on the teachingsdescribed herein, a person of ordinary skill in the art can conductclinical studies to determine empirically the thickness and moduluscorresponding to a relative rigidity of the inner portion 110 for thecovering 100 so as to smooth irregularities and conform substantially tothe ablation zone.

TABLE A2 Pressure for 5 μm deflection at diameters of 3, 4, 5 and 6 mmfor coverings of Table A1. Pressure Required to obtain 5 Button Relativeum deflection (Pa) Button Thickness Rigidity 3 mm 4 mm 5 mm 6 mmMaterial (um) (Pa*m{circumflex over ( )}3) span span span span Rigid 2505.47E−04 1002.2 317.1 129.9 62.6 Silicone Rigid 200 2.80E−04 513.1 162.466.5 32.1 Silicone Rigid 150 1.18E−04 216.5 68.5 28.1 13.5 SiliconeRigid 100 3.50E−05 64.1 20.3 8.3 4.0 Silicone Rigid 50 4.38E−06 8.0 2.51.0 0.5 Silicone Exemplary 293 5.03E−04 921.9 291.7 119.5 57.6 SiliconeExemplary 272 4.02E−04 737.6 233.4 95.6 46.1 Silicone Exemplary 2503.13E−04 572.7 181.2 74.2 35.8 Silicone Exemplary 215 1.99E−04 364.3115.3 47.2 22.8 Silicone Exemplary 200 1.60E−04 293.2 92.8 38.0 18.3Silicone Exemplary 175 1.07E−04 196.4 62.2 25.5 12.3 Silicone Exemplary150 6.75E−05 123.7 39.1 16.0 7.7 Silicone Exemplary 100 2.00E−05 36.711.6 4.8 2.3 Silicone Exemplary 50 2.50E−06 4.6 1.4 0.6 0.3 Siliconeenflufocon 25 2.97E−05 54.4 17.2 7.1 3.4 A (Boston ES) enflufocon 502.38E−04 435.2 137.7 56.4 27.2 A enflufocon 150 6.41E−03 11751.3 3718.21523.0 734.5 A hexafocon 25 1.81E−05 33.2 10.5 4.3 2.1 B (Boston XO2)hexafocon 50 1.45E−04 265.7 84.1 34.4 16.6 B hexafocon 150 3.92E−037174.5 2270.1 929.8 448.4 B

The data of Table A1 and A2 show that the pressure to deflect a 3 mmzone a distance of 5 μm can be about three times the pressure to deflecta 4 mm zone the distance of 5 μm, and about 15 times the pressure todeflect the 6 mm zone the 5 μm distance. For example, for the relativerigidity of about 3.13E-4 (Pa*m{circumflex over ( )}3), the 5 μmdeflection pressures are 572.7, 181.2, 74.2, 35.8 (Pa) for diameters of3, 4, 5 and 6 mm, respectively, such that the central 3 mm of innerportion 110 can provide a compressive force to irregularities of about570 Pa when the inner portion 110 conforms to the ablation across a 6 mmspan with a pressure of about 35 Pa, for example. By comparison withintraocular pressure (TOP) measure in mm of Hg, 12 mm of Hg is about1,600 Pa, such that the coverings may conform to the cornea, for exampleover a 6 mm region, when the eye blinks. This conformation of thecovering to the cornea when the eye blinks can provide pumping inaccordance with embodiments as described herein.

The relative rigidity and deflection pressures can be determined formany coverings based on the teachings described herein, for example forcoverings having a plurality of layers having a plurality of materials.

TABLE A3 Relative Rigidity of Layered Coverings Material 2 (Soft)Composite Material 1 (Rigid) Flexural Composite Relative Total LayeredThickness Modulus Thickness Modulus Thickness Modulus Rigidity ThicknessMaterial (m) (Pa) (m) (Pa) (m) (Pa) (Pa*m{circumflex over ( )}3) 270 μmExemplary 2.40E−04 2.00E+07 3.00E−05 2.00E+06 2.70E−04 1.80E+07 3.54E−04thick Silicone Shield Soft and 1.35E−04 2.00E+07 1.25E−04 2.00E+062.70E−04 1.13E+07 1.99E−04 Hard are Equal 150 μm Exemplary 1.20E−042.00E+07 3.00E−05 2.00E+06 1.50E−04 1.64E+07 5.54E−05 thick SiliconeShield Soft and 7.50E−05 2.00E+07 7.50E−05 2.00E+06 1.50E−04 1.10E+073.71E−05 Hard w/ Equal thickness

When two or more materials are combined so as to provide two or morelayers, the relative rigidity of each layer can be combined so as todetermine a total composite rigidity. For example, the combined rigiditycan be determined for a covering having first layer 110L1 of firstmaterial, a second layer 110L2 of second material M2 and third layer110L3 of third material 110L3, in which the first and third materialscan be the same material.

A weighted average system can be used to treat the two layers as onematerial. The relative amounts of each material and the moduli of thetwo materials can be combined to determine a composite modulus based onthe weight average of the thickness of each layer. For example, with 90μm of 20 Mpa material layer and a 10 μm of 5 MPa material layer can becombined so as to determine the composite modulus as

20 MPa*0.9+5 MPa*0.1=18.5 MPa

The equations described herein accommodate many layers of differentmaterials and thicknesses.

Based on the composite modulus, one can multiply the composite modulusby the overall thickness cubed, in the present example 18.5MPa*100{circumflex over ( )}3. Although these calculations can be basedon approximations, a person of ordinary skill in the art can conductsimulations, for example finite element modeling simulations, so as todetermine the amount of relative rigidity, pressures and deflectionforces and pressures as described herein.

The index of refraction of one or more layers of covering 100 maycorrespond substantially to the index of refraction of the cornea.

One or more of the materials 110M1, 110M2 or 110M3 may comprise an indexof refraction within a range from about 1.38 to about 1.43 so as tomatch the index of refraction of the cornea to within about +/−0.05. Forexample the materials 110M1 and 110M3 may comprise an opticallytransparent soft silicone elastomer having an index of refraction ofabout 1.41 and the material M2 may comprise an optically transparentrigid silicone elastomer having an index of refraction of about 1.43,for example available from NuSil. Alternatively, material 110M1 andmaterial 110M3 may comprise silicone hydrogel and material 110M2 maysilicone, for example.

While the covering may comprise similar materials such as a more rigidsilicone combined with a softer silicone, the covering may comprisedissimilar materials. For example, and RGP material can be combined witha hydrogel, such as the bicurve or tricurve embodiments as describedherein. The covering can extend at least to the limbus for stability.The RGP material may comprise the second layer 110L2 of the secondmaterial 110M2, for example in accordance with Table A1, and thehydrogel may comprise the first layer 110L1 of the first material 110M1and the third layer 110L3 of the third material 110M3. The hydrogel mayhave an index of refraction from about 1.38 to about 1.42 so as to matchthe index of refraction of the cornea of about 1.377 to within about0.05 and may comprise one or more of HEMA, NVP, GMA, MMA, SiH, TRS,HEMA/NVP, MMA/NVP, HEMA/GMA, or SiH/TRS, commercially available fromVista Optics, UK, for example. The hydrogel comprising HEMA/NVP,MMA/NVP, or HEMA/GMA may have water content within a range from about40% to about 70% so as to comprise the index of refraction within therange from about 1.38 to about 1.43. A water content of about 40%corresponds to an index of refraction of about 1.43 and a water contentof about 70% corresponds to an index of refraction of about 1.38. Thehydrogel comprising SiH/TRS may comprise water content within a rangefrom about 20% to about 70% so as to comprise the index of refractionwithin the range from about 1.38 to about 1.43. With these SiH hydrogelsa water content of about 20% corresponds to an index of refraction ofabout 1.43 and a water content of about 70% corresponds to an index ofrefraction of about 1.38.

FIG. 2A shows a covering 100 comprising a contact lens placed on the eyewith the eyelids separated, in accordance with embodiments. The covering100 is placed on the eye such that the tear liquid TL extends under atleast a portion of the covering between the covering and the cornea soas to provide a chamber 100C. The covering 100 can be fit on K orslightly flatter than the cornea so as to provide chamber 100C.Alternatively or in combination, the flange 120F and sclera couplingportion 120S of the outer portion 120 may comprise an angle steeper thanthe conjunctiva such the covering is urged away from the cornea nearinner portion 110 so as to provide chamber 100C. The covering 100comprises a sag height 105S1 corresponding to the elevation distancefrom the center of the covering to the outer perimeter 120P of thesclera coupling portion 130. The eyelids can be separated for thepatient to see an object.

FIG. 2B shows a side sectional view of the covering of FIG. 2A with theeyelids closing.

FIG. 2C shows a front view the covering of FIG. 2A with the eyelidsclosing, in accordance with embodiments. The eyelids can close with adownward movement 22A of the upper eyelid and an upward movement 22B ofthe lower eyelid. The closing of the eyelids exerts pressure on thecovering 100 such that covering 100 comprises second configuration100C2. The second configuration 100C2 comprises the sag height 105decreased to second sag height 105 S2 such that the volume of chamber100C decreases and urges pumped tear fluid 100TL from under thecovering. The pumped tear liquid 100TL flows radially outward under theouter portion 120P and through fenestrations 100F such as fenestrationsnot covered by the eyelid. The pressure of the eyelid can urge thecovering 100 toward cornea 100 so as to decrease the volume of chamber100C. The volume of chamber 100C can decrease substantially when theouter portion 120 comprising flange 120F deflects with elasticdeformation. Alternatively or in combination, the outer portion 120corresponding to the cornea can deflect so as to decrease the volume ofchamber 100C. In many embodiments, the inner portion 110 comprisingoptical component 100A may deflect with pressure of the eyelid so as todecrease the volume of chamber 100.

FIG. 2D shows side profile the covering of FIG. 2A with the eyelidsopening, in accordance with embodiments. When the eyelids retract withupward movement 22C of the upper eyelid and downward movement 22D of thelower eyelid, the covering 100 can return to the first configuration100C1 having first sag height 105S1, such that the volume of the chamberincreases. The outer portion 120 comprising flange 120F and peripheralportion 120F of the sclera coupling portion 130 may contact theconjunctiva so as to form a contact seal with the conjunctiva. Thecontact seal with the conjunctiva encourages flow of the tear liquid TLthrough the fenestrations 100F and into the chamber 100C, such thatpumped tear liquid 100TL can be located between the cornea and thecovering 100.

The tear rivulet of the lower lid can move upward when the eyes close soas to provide tear liquid on the surface of the eye, and at least aportion of the rivulet can couple to the upper lid when the lids contacteach other. When the upper lid moves upward with movement 22C and thelower lid moves downward with movement 22D, the upper lid provide tearliquid TL near the upper fenestrations to pass through the upperfenestrations and the lower lid can provide tear liquid TL near thelower fenestrations to move through the lower fenestrations.

Repeated blinking of the eye may occur naturally, so as to pump tearliquid under the covering and rinse the cornea and conjunctiva under thecovering. This pumping and rinsing provided by the covering can extendthe amount of time the covering can be worn by a patient such as apatient having a normal unablated eye, and may encourage epithelialregenerations in post PRK eyes, for example.

FIG. 2E shows a covering comprising a contact lens placed on the eyesuch that the covering is supported with an inner portion of the corneaand the conjunctiva with the covering separated from an outer portion ofthe cornea so as to define a chamber when the eyelids are separated, inaccordance with embodiments. The covering 100 may contact the cornea atan inner portion of the cornea, for example at a central location. Theinner portion 110 can be sized to fit the cornea centrally as describedherein, for example with on K fitting. The outer portion of the covering120 comprising flange 120F and sclera coupling portion 130 can be sizedto contact the conjunctiva when the inner portion 110 contacts thesclera centrally, such that chamber 100C is formed over the outerportion of the cornea with a gap extending between the outer portion ofthe cornea and the covering. The outer portion 120 of the coveringextending over the outer portion of the cornea may have a curvature lessthan the cornea, such that the outer portion 120 over the outer portionof the cornea can form chamber 100C when the inner portion 110 issupported with the cornea and the outer portion 120 comprising flange120F is coupled to the conjunctiva. The fenestrations 100F can belocated on the covering to correspond with a location of chamber 100Cand the gap when the eyelids are open. The outer portion 120 comprises aresistance to deflection sufficient to form chamber 100C when theeyelids are open an insufficient to resist deflection when the eyelidsmove over the outer portion such that the outer portion moves toward thecornea and decrease the gap distance when the eyelids close.

The covering 100 can be fit to the cornea to encourage formation of thechamber 100C and such that covering 100 comprises an initialconfiguration 100C1 with chamber 100C formed beneath. The cornea maycomprise a limbus sag height 105L corresponding to an elevationaldistance extending from a vertex of the cornea to the limbus. The limbusmay be located a radial distance 105RL from a measurement axis of theeye. The eye may comprise a conjunctiva sag height 105C at a radialdistance 105RC from the axis of the eye. The covering may comprise alimbus sag height 105LC at a location corresponding to the radialdistance RL to the limbus. The covering may comprise a conjunctiva sagheight 105CC at a conjunctiva contacting location corresponding to theradial distance 105RC of the conjunctiva, for example along flange 120F.In many embodiments, the sag height 105LC of the covering at thelocation corresponding to the limbus is no more than the limbus sagheight 105L, and the sag height 105CC of the covering at the locationcorresponding to the conjunctiva is no more than the conjunctiva sagheight 105C, such that pressure to the limbus is decreased. When thecovering is placed on the eye, the conjunctiva coupling portion 130comprising flange portion 120F can deflect such that the sag height ofthe conjunctiva contacting portion is decreased from 105CC the sagheight of the conjunctiva to the sag height of the conjunctiva 105C,such that the sag height of the covering comprises a sag deflected sagheight 105S2.

FIG. 2F shows a side sectional view of the covering of FIG. 2E with theeyelids closing such that covering 100 comprises a configuration 100C2with chamber 100C having a decreased volume. When the eyelids close, theupper and lower lids exert pressure on the covering such that thecovering is urged toward the outer portion of cornea and theconjunctiva. The outer portion of the covering over the outer portion ofthe cornea may not have sufficient resistance to deflection such thatthe outer portion of the covering is deflected downward toward the outerportion of the cornea. The gap distance extending between the outerportion of the covering over the outer portion of the cornea isdecreased, such that the volume of chamber 100C decreases and pumpedtear liquid 100TL flow from chamber 100C through fenestrations 100F andunder the conjunctiva contacting portion 130 comprising flange portion120F. The upper eyelid can extend across the pupil so as to coverinferior and superior fenestrations 100F. The upper eyelid may contactthe lower eyelid so as to draw the tear liquid of the rivulet superiorlywhen the eye opens, such that tear liquid of the rivulet can be drawninto the chamber through the inferior and superior fenestrations.

The deflection of the outer portion of the covering over the outerportion of the cornea can be provided with a covering having a relativerigidity within a range from about 1.0 E-6 Pa*m{circumflex over ( )}3 toabout 6 E-4 Pa*m{circumflex over ( )}3, for example from about 2.5 E-6Pa*m{circumflex over ( )}3 to about 5 E-4 Pa*m{circumflex over ( )}3.Table A2 shows values suitable of relative rigidity and correspondingranges of outer portion 120 corresponding to the outer portion of thecornea that can be determined based on the teachings described herein soas to determine the relative rigidity of the outer portion of thecovering to provide resistance to deflection and form the chamber withthe gap when the eyelid is away from the portion of the covering and soas to deflect toward the cornea and decrease the gap and correspondingchamber volume when the eyelid covers the portion of the covering.

The deflection of the sclera contacting portion 130 to couple to theconjunctiva can be provided with the sclera contacting portion 130comprising a relative rigidity of no more than about 2 E-4Pa*m{circumflex over ( )}3, for example no more than about 1 E-4Pa*m{circumflex over ( )}3, and in many embodiments no more than about 2E-5 Pa*m{circumflex over ( )}3. Table A2 shows values suitable ofrelative rigidity and corresponding ranges of sclera coupling portion130 that can be determined based on the teachings described herein so asto determine the relative rigidity of the sclera coupling portion of thecovering to provide resistance to deflection and form the chamber withthe gap when the eyelid is away from the portion of the covering and soas to deflect toward the cornea and decrease the gap and correspondingchamber volume when the eyelid covers the outer portion of the coveringover the outer portion of the cornea.

The deflection of the flange portion 120F to couple to the conjunctivacan be provided with the flange portion 130 comprising a relativerigidity of no more than about 1 E-4 Pa*m{circumflex over ( )}3, forexample no more than about 2 E-5 Pa*m{circumflex over ( )}3, and in manyembodiments no more than about 2.5 E-6 Pa*m{circumflex over ( )}3. TableA2 shows values suitable of relative rigidity and corresponding rangesof outer flange portion 120F that can be determined based on theteachings described herein so as to determine the relative rigidity ofthe flange portion 120F of the covering to provide resistance todeflection and form the chamber with the gap when the eyelid is awayfrom the portion of the covering and so as to deflect toward the corneaand decrease the gap and corresponding chamber volume when the eyelidcovers the outer portion of the covering over the outer portion of thecornea.

FIG. 2F1 shows a side sectional view of the covering of FIG. 2F withrotation of the eye when the lids close such that sliding of thecovering along the epithelium is inhibited when tear liquid is pumped,in accordance with embodiments. The axis of the eye can rotatesuperiorly such that the covering slides along the upper lid and thelower lid. The axis of the eye may comprise one or more known axis ofthe eye and can be determined in many ways by a person of ordinary skillin the art.

FIG. 2G shows a side view sectional view of the covering of FIG. 2E withthe eyelids opening, in accordance with embodiments. The opening of theeyelids decreases pressure and allows the outer portion of the coveringabove the outer portion of the cornea to move away from the cornea. Thetear liquid TL may pass through fenestrations 100F and into the chamber100C. The outer portion of the covering comprising portion 130 andflange 120F can contact the conjunctiva to inhibit tear flow and mayseal the covering.

FIG. 2H shows a side view sectional view of the covering of FIG. 2E withthe eyelids located at an intermediate location such that the chambercomprises an intermediate configuration 100C12 volume, in accordancewith embodiments. The optical component 100A comprising inner portion110 may comprise sufficient rigidity and resistance to deflection so asto provide vision for the patient when the covering comprisesintermediate portion 100C12 having outer portion 120 deflected so as todecrease volume of chamber 100C. For example, the patient can close theeyelids to the pupil margin to deflect the outer portion and the opticalcomponent 100B and inner portion 110 can remain substantiallyundeflected such that the patient can have vision of 20/20 or better(metric 6/6 or better) with a portion of one or more eye lids contactingthe inner portion 110. Opening of the eyelids can increase the chambervolume and pump tear liquid and closing of the eyelids can decreasechamber volume and pump tear liquid.

FIG. 2I shows a side view sectional view of the covering of FIG. 1C4placed on the eye with hydrogel contacting the eye. The covering 100comprises the layer of hydrogel material 120MHG extending along theposterior surface of the covering so as to contact the eye with at leasta portion of the hydrogel layer. The covering 100 can be dimensioned toform chamber 100C defined at least in part with the layer of hydrogelmaterial. The fenestration may extend through the hydrogel layer so asto provide pumping as described herein. Alternatively or in combination,the posterior end of the fenestration can be covered with the hydrogelmaterial to couple the cornea to the fenestration with the layer ofhydrogel material. The fenestrations covered with the layer of hydrogelmaterial 120MHG can be located along the deflectable portion of thecovering so as to encourage movement of water and therapeutic agentsalong the hydrogel material, for example when the eye blinks. Thehydrogel layer may comprise a medium to pass liquid and therapeuticagent from the fenestration to a desired location of the cornea, forexample with wicking of the liquid and therapeutic agent to a centrallocation of the cornea. The covering comprising the hydrogel layerextending along the lower surface as described herein can be fit to anunablated eye to provide refractive correction or fit to an ablated eyeas described herein.

Clinical testing in accordance with embodiments has shown that thecurved portions of the covering can be fit with on K-values inaccordance with corneal curvatures and sag heights and limbus sagheights and conjunctiva sag heights of a patient population.

Appendix I shown herein below provides dimensions and fit parameters forcovering 100 in accordance with embodiments and teachings as describedherein. The coverings may comprise one or more of the materials in theSeries A Tables shown herein, for example. The dimensions and fitparameters of the coverings can provide pumping of the tear liquid whenplaced on the cornea in accordance with embodiments described herein.The tables of Appendix I identify the coverings for use with steep Kcorneas, medium K corneas and flat K corneas, for example. The K valueslisted can be based on population norms, such that the coverings providepumping as described herein when placed on the eye. The coverings can beused with non-ablated eyes or ablated eyes, and the covering can beidentified at least in part based on the first inner curvature R1.

Table B1 shows covering 100 having a diameter of approximately 14 mmacross and can be fit on K or flatter, for example as described herein.The table lists R1 corresponding to the center ablated portion of thecornea. The inner portion 110 comprising optical component 100A andinner coupling component 100B1 has dimension R1 extends about 5 mmacross, and the ablation zone can be larger, for example about 6 mm. Theportion corresponding to radius R1B1 has dimensions of about 5-7 mmacross, and the curvature can be expressed with keratometry values(K-values) corresponding to the optical power of the eye in Diopters(D). The portion corresponding to radius R1B2 has dimensions of about7-9 mm across. The portion corresponding to radius R1B3 has dimensionsof about 9-11 mm across. The portion corresponding to R1C1 can extendfrom about 11 to 13.5 mm across, and may comprise curvature having oneor more values between portion R1B3 and portion R1C2, for example aradius of curvature between about 8 mm and about 12 mm such as about 10mm. The portion corresponding to R1C2 can extend from about 13.5 to 14mm across. The sag height of the portion R1C2 can be from about 3.1 toabout 3.4 mm, for example. The portion corresponding to R1C1 can be fitto the cornea in many ways as described herein, for example with thetangent of portion R1C1 aligned with R1B3 on the inner boundary and R1C2along an outer boundary so as to inhibit ridge formation as describedherein.

Table B2 shows covering 100 having a diameter of approximately 14 mmacross and can be fit on K or flatter, for example as described herein.The table lists R1 corresponding to the center ablated portion of thecornea. The inner portion 110 comprising optical component 100A andinner coupling component 100B1 has dimension R1 extends about 5 mmacross, and the ablation zone can be larger, for example about 6 mm. Theportion corresponding to radius R1B1 has dimensions of about 5-7 mmacross, and the curvature can be expressed with keratometry values(K-values) corresponding to the optical power of the eye in Diopters(D). The portion corresponding to radius R1B2 has dimensions of about7-9 mm across. The portion corresponding to radius R1B3 has dimensionsof about 9-11 mm across, and these values range from about 35.75 toabout 40, such that each value is somewhat flatter at the peripheralportion than corresponding values of Table B 1. For example, Table B1lists the values for R1B3 as having a range from about 36.75 to about 41D. The portion corresponding to R1C1 can extend from about 11 to 13.5 mmacross. The portion corresponding to R1C2 can extend from about 13.5 to14 mm across. The sag height of the portion R1C2 can be from about 3.1to about 3.4 mm, for example. The portion corresponding to R1C1 can befit to the cornea in many ways as described herein, for example with thetangent of portion R1C1 aligned with R1B3 on the inner boundary and R1C2along an outer boundary so as to inhibit ridge formation as describedherein.

Table B3 shows covering 100 having a diameter of approximately 16 mmacross and can be fit on K or flatter, for example as described herein.The table lists R1 corresponding to the center ablated portion of thecornea. The inner portion 110 comprising optical component 100A andinner coupling component 100B1 has dimension R1 extends about 5 mmacross, and the ablation zone can be larger, for example about 6 mm. Theportion corresponding to radius R1B1 has dimensions of about 5-7 mmacross, and the curvature can be expressed with keratometry values(K-values) corresponding to the optical power of the eye in Diopters(D). The portion corresponding to radius R1B2 has dimensions of about7-9 mm across. The portion corresponding to radius R1B3 has dimensionsof about 9-10.5 mm across, and these values range from about 36.75 toabout 41. The portion corresponding to R1C can extend from about 13 toabout 16 mm across. The sag height of the portion R1C2 can be less thanabout 3.6 mm, for example, such that portion R1C2 can be deflected whenplaced on the eye. The portion corresponding to R1C1 can be fit to thecornea in many ways as described herein.

Table B4 shows covering 100 having curvatures for use with non-ablatedeyes so as to pump tear liquid as described herein, for example with anextended wear contact lens. Covering 100 has a diameter of approximately14 mm across and can be fit on K or flatter, for example as describedherein. The table lists R1 corresponding to the center ablated portionof the cornea. The inner portion 110 comprising optical component 100Aand inner coupling component 100B1 has dimension R1 extends about 5 mmacross. The curvatures of the inner portion corresponding to R1 havecurvature values corresponding to optical powers from about 39 D toabout 48D, which can be based on population data for unablated eyes andcombined with the curvatures for portions R1B1 to R1B3 and R1C1 andR1C2, for example. The portion corresponding to radius R1B1 hasdimensions of about 5-7 mm across, and the curvature can be expressedwith keratometry values (K-values) corresponding to the optical power ofthe eye in Diopters (D). The portion corresponding to radius R1B2 hasdimensions of about 7-9 mm across. The portion corresponding to radiusR1B3 has dimensions of about 9-11 mm across. The portion correspondingto R1C1 can extend from about 11 to about 13.5 mm across. The portioncorresponding to R1C2 can extend from about 13.5 to 14 mm across. Thesag height of the portion R1C2 can be from about 3.1 to about 3.4 mm,for example. The portion corresponding to R1C1 can be fit to the corneain many ways as described herein, for example with the tangent ofportion R1C1 aligned with R1B3 on the inner boundary and R1C2 along anouter boundary so as to inhibit ridge formation as described herein.

Although Tables B1-B4 list specific curvature values by way of example,a person of ordinary skill in the art can determine many curvaturevalues based on the teachings and embodiments described herein and oneor more of the curvatures can be combined with an aspheric surface, forexample an aspheric surface having a conic constant.

FIG. 3A shows a covering 100 positioned on cornea 10 an eye 2 having anepithelial defect 11. The covering may comprise a curved body, forexample a curved contact lens body shaped to fit the cornea.

The covering 100 can be sized to cover the ablated profile andepithelial defect. The inner portion 110 comprises a dimension across102 that can be sized to extend across a majority of the ablation, andthe outer portion 120 comprises a dimension across 104 sized to extendacross at least the epithelial defect and contact the epithelium onopposite sides of the defect.

The dimension 102 extending across a majority of the ablation may extendabout 6 to 8 mm, for example, and may be sized larger than the ablation.The dimension 104 may comprise about 12 to 14 mm across, for example soas to extend to the limbus and can be sized to the limbus of the patientfor example. Work in relation to embodiments suggests that the coveringsized to extend to the limbus and circumferentially around the limbuscan be centered on the cornea. The covering may extend such that theouter rim of the covering contacts the conjunctiva disposed above thesclera peripheral to the limbus, for example, and that suchconfigurations may center the lens on the cornea, for example.

The thickness of the covering can be sized and shaped in many ways. Theinner portion 110 of the covering comprises a thickness 106 and theouter portion 120 of the covering comprises a thickness 108. Thethickness 106 of the inner portion may comprise a substantially uniformthickness such that the inner portion comprises an optical power of nomore than about +/−1D prior to placement on the eye, for example whenheld in front of the eye and separated from the cornea by a distance.Alternatively, the thickness of the inner portion may vary so ascomprise optical power, for example optical power to correct vision ofthe patient.

A smooth layer 12S of regenerated epithelium 12R may substantially coveran ablated profile. The environment 100E is configured to guideepithelial regeneration and smooth the regenerated epithelium. Theregenerating epithelium comprises a thickness profile 12RP.

The epithelium grows centripetally from circumscribing boundary 12Etoward the center of ablated profile 20 to cover the exposed stroma, asindicated by arrows 30.

The covering 100 may comprise an inner portion 110 and an outer portion120. The outer portion 110 can be configured to form a seal 100S withthe cornea near the edge of the ablation and the epithelial defect, forexample with a soft conformable material such as silicone elastomer orsilicone hydrogel. The inner portion 120 is positioned over the pupiland configured for the patient to see, and may comprise a rigiditygreater than the outer portion, so as to smooth irregularities of theepithelium when the cornea heals. Alternatively, the inner portion maycomprise rigidity equal to or less than the rigidity of the outerportion as well. For example, the inner portion may comprise siliconeand the outer portion may comprise silicone, and the inner portion maycomprise one or more of a more rigid silicone or a greater thicknesssuch that the inner portion can be more rigid than the outer portion soas to smooth the epithelium. Although the inner portion can be morerigid than the outer portion, the inner portion can be sufficientlysoft, flexible and conformable so as to conform at least partially tothe ablated profile 20 in the stroma, such that the patient receives thebenefit of the vision correction with the ablation profile 20 when thepatient looks through the inner portion and the inner portion smoothesthe epithelium. Work in relation to embodiments of the present inventionsuggests that the regenerating epithelium is softer than the underlyingstroma of ablation profile 20, such that the inner portion can beconfigured to conform to the shape of the ablation profile 20 when theinner portion smoothes the epithelium disposed under the inner portion,for example with deflection pressure as described herein.

FIG. 3B shows covering 100 in a first configuration prior to placementon the cornea of an eye having an epithelial defect, such as an eyehaving a PRK ablation. The covering 100 comprises fenestrations 100F.The fenestrations 100F can be located on the covering such that thefenestrations are located away from the epithelial defect to pump tearliquid under the covering as described herein. The covering 100 maycomprise inner portion 110 having a base radius R1 of curvature, and thebase radius of curvature may be slightly longer than the ablated corneasuch that the covering can be flatter than the cornea prior to placementon the cornea. The outer portion 120 comprising sclera coupling portion130 may comprise a portion steeper than the cornea to reduce pressure tothe limbus. For example flange portion 120F can be steeper than thecorresponding portions of conjunctiva and sclera so as to decreasepressure of the covering on the limbus.

The base radius R1 can be sized to the cornea in many ways. For example,the base radius R1 may have a radius corresponding to the post ablatedeye.

The covering 100 may comprise a modulus within a range from about 4 MPato about 35 MPa, such that central portion can conform at leastpartially to the ablated stroma and so that the covering can smoothcorneal irregularities and stromal irregularities of the ablated cornea.The covering may comprise an elastomeric stretchable material such thatthe covering can stretch to fit the cornea, for example. The coveringhaving the modulus within a range from about 4 MPa to about 35 MPa canbe formed in many ways as described herein. For example, the coveringmay comprise a single piece of material having a substantially uniformthickness extending across the ablated cornea and at least a portion ofthe unablated cornea, and the single piece of material may comprise anelastic material such as a silicone elastomer or a hydrogel.Alternatively, the covering may comprise a single piece of materialhaving a non-uniform thickness extending across the ablated cornea andat least a portion of the unablated cornea. The covering can be shapedin many ways and may comprise a single piece of one material, or maycomprise a single piece composed to two similar materials, or maycomprise a plurality of materials joined together.

The covering 100 may comprise one or more outer portions extendingoutside the inner portion as described herein.

FIG. 3C shows the covering of FIG. 3B placed on the eye having a secondconfiguration 100C2 conforming to ablated stromal tissue and smoothingthe epithelium over the ablated stroma, such that the covering can pumptear liquid as described herein. The cornea comprises an ablated surface20 to correct vision that may have a corresponding radius of curvature,for example radius R2. The ablated profile 20 may comprise additional,alternative, or combinational shapes with those corresponding to radiusR2, such as aberrations ablated into the cornea to correct aberrationsof the eye and astigmatism ablated into the cornea, and the innerportion 110 of covering 100 can conform to these ablated profiles of thecornea such that the patient can receive the benefit of the ablativevision correction when the covering is positioned on the cornea. Forexample, the cornea ablation profile 20 may correspond to radius ofcurvature R2, and the inner portion 110 can flatten from configuration100C1 corresponding to radius of curvature R1 prior to placement to asecond configuration 100C2 corresponding substantially to the ablatedprofile 20, such the patient can see with the benefit of ablationprofile 20. For example, the second configuration 100C2 can comprise aconforming radius of curvature R12 that corresponds substantially toradius of curvature R2. The profile corresponding to the firstconfiguration 100C1 of the covering 100 is shown positioned over cornea10 to illustrate the change in profile of the covering fromconfiguration 100C1 prior to placement to conforming configuration 100C2of the covering 100 when positioned on the cornea.

The conformable covering 100 comprises sufficient rigidity so as tosmooth the epithelium when covering 100 is positioned on the cornea overthe ablation profile 20. The epithelium comprises a peripheral thickness12T that may correspond substantially to a thickness of the epitheliumprior to debridement of the epithelium to ablate the cornea. Theepithelium also comprises regenerating epithelium 12R disposed over theablation profile 20. The covering 100 can smooth the epithelium 12R whenconforming to the cornea in the second configuration 12C2. For example,irregularities 121 of the regenerating epithelium 12R disposed over theablation can be smoothed when the epithelium regenerates along the innerportion of covering 100, such that the irregularities 121 of theregenerating epithelium 12R are thinner than the thickness 12T of theperipheral epithelium.

Work in relation to the embodiments as described herein indicates thatan at least partially conformable covering having a modulus within arange from about 4 MPa to about 35 MPa can conform at least partially tothe ablated stroma and smooth irregularities of the epithelium andstroma so as to improve vision as described herein. The covering havingthe modulus within the range from about 4 MPa to about 35 MPa can beformed in many ways as described herein.

FIGS. 4A to 4H show a method 400 of manufacturing a covering 100 andapparatus for manufacturing the covering as described herein.

FIG. 4A shows a mold 600A to form an optical component 100A of acovering 100 comprising material 110M as described herein. The opticalcomponent 100A may comprise an optically transparent material such as asilicone, for example. The optical component may comprise a modulus andthickness and corresponding rigidity as described herein, so as toprovide vision and smoothing of the cornea. The mold 600A may comprisean optical correction on one surface and a base curvature on theopposite surface, for example. With a step 410, the optical component100A can be formed in mold 600A.

FIG. 4B shows a mold 600B to form a covering comprising the opticalcomponent of FIG. 4A and the coupling component 100B. The opticalcomponent 100A can be placed in the mold and the flowable material 120Mof the coupling component injected into the mold so as to form thecovering. The solid inner component comprising a rigid material placedtherein prior to injection of a flowable material. The mold 600B maycomprise inner material 110M positioned within the mold as a solid pieceof material and outer material 120M comprising a flowable materialinjected into mold 600B and cured around the preformed piece comprisinginner material 120M. The flowable material can be injected around theinner material 100M in many ways. For example, the inner material 110Mmay comprise a second layer 110L2 of rigid material 110M2 of the innerportion 110 as described herein, and the flowable material can beinjected around the upper and lower surfaces of second material 110M2 soas to form a first layer 110L1 of first material 110M1 and a third layer110L3 of the third material 110M3 with the flowable material such thatthe first material 110M1, the third material 110M3 and the outermaterial 120M each comprise substantially the same soft material whencured. With a step 420, the covering comprising the optical component100A and the coupling component 100B can be formed

FIG. 4C shows a mold 600C to form a covering comprising the opticalcomponent of FIG. 4A and a layer of a soft material of the covering,such that the optical component can be located between two layers of thecoupling component. The optical component 100M can be removed from themold as shown in FIG. 4A and placed in the mold 600C. The flowablematerial M3 corresponding to layer 110L3 can be injected into the moldand cured. The partially formed inner component comprising layer 110L2and layer 110L3 can be removed from mold 600C. With a step 430, theportion of the covering comprising the two layers can be formed.

FIG. 4D shows a mold 600D to form a covering and having a solid innercomponent comprising the rigid material placed for injection of aflowable material, in accordance with embodiments of the presentinvention. The mold 600 may comprise inner material 110M positionedwithin the mold as a solid piece of material and outer material 120Mcomprising a flowable material injected into mold 600 and cured aroundthe preformed piece comprising inner material 600. The mold may comprisean upper portion and a lower portion. In many embodiments, the covering100 can be formed in a mold with rigid second material 110M2 placed inthe mold and encapsulated within a single piece of material comprisingfirst material 110M1, third material 110M3 and outer material 120M, suchthat first material 110M1, third material 110M3 and outer material 120Mcomprise the same material, for example silicone. The rigid secondmaterial 110M2 may comprise silicone bonded to each of first material110M1, third material 110M3 and the outer material 120M, for examplewith curing such that first material 110M1, third material 110M3 andouter material 120M comprise the same soft silicone material bonded tothe second material 110M2 comprising rigid silicone. With a step 440,the covering comprising the solid inner component between first material110M1 and third material 110M3 can be formed.

FIG. 4E shows formation of fenestrations in the covering with energy.With a step 450 the covering as described in FIG. 4B or 4D can betreated with energy 650, for example mechanical energy orelectromagnetic energy such as light energy to form the fenestrationextending through the covering. For example, the fenestration can beremoved from the mold and mechanically punched or ablated with laserlight energy to form the fenestration.

FIG. 4F shows spin coating of a hydrogel material on a posterior surfaceof the covering. An amount of a curable hydrogel forming material 660 asdescribed herein can be deposited on the posterior surface of thecovering and spun with rotation 662 at rate such that the coating movesaway from a center of the covering toward and outer boundary of thehydrogel material. The outer boundary of the hydrogel material can bedetermined based on the amount of curable material 660 and spin rate,and the curable hydrogel material can be formulated to provide thedesired thickness as described herein, for example a substantiallyuniform thickness within a range from about 1 μm to about 100 μm whenfully hydrated. With a step 460, the curable hydrogel forming material660 can be cured so as to provide the layer of hydrogel material on thelower surface of the covering 100.

FIG. 4G shows chemical vapor deposition on the covering having thehydrogel material formed thereon. The covering 100 can be placed in achemical vapor deposition chamber 670, and treated with one or moreforms of chemical vapor deposition as described herein. With a step 460,the covering 100 can be coated with the CVD to provide the wettablematerial on the surface of the covering.

FIG. 4H shows the covering comprising 100 the hydrogel material 120HGpackaged in a container 680. The covering can be sterilized, and can bepackaged wet or dry, or combinations thereof in container 680. Forexample, the covering can be placed with a fluid comprising saline inthe container. Alternatively, the covering 100 can be dry packaged incontainer 680, for example. With a step 480, the covering 100 can beplaced on container 680 and the container sealed.

It should be appreciated that the specific steps illustrated in method400 provide a particular method of manufacturing a covering, accordingto an embodiment of the present invention. Other sequences of steps mayalso be performed according to alternative embodiments. For example,alternative embodiments of the present invention may perform the stepsoutlined above in a different order. Moreover, the individual stepsillustrated may include multiple sub-steps that may be performed invarious sequences as appropriate to the individual step. Furthermore,additional steps may be added or removed depending on the particularapplications. One of ordinary skill in the art would recognize manyvariations, modifications, and alternatives.

A Method 500 of manufacturing covering 100 comprising a contact lens topump tear liquid may comprise one or more of the following steps:

505—Provide first mold for optical component

510—Inject first flowable material into first mold

515—Cure first flowable material to form first optical component

520—Remove first optical component from first mold

525—Place first optical component in second mold

530—Inject second curable material into second mold

535—Cure second flowable material to form second component

540—Remove second component from second mold

545—Place second component in third mold

550—Inject third flowable material into third mold

555—Cure third flowable to form covering

560—Remove covering

565—Drill fenestrations

570—Coat with wettable material

The rigidity and hardness of the molded covering can be determined byone or more of the material hardness, the modulus or the thickness. Themolded covering may comprise a covering with an inner center more rigidthan the outer periphery, for example, and the center can be thickerthan edge. For example, the covering may comprise a single piececovering with an inner portion thicker than the outer portion such thatthe inner portion is more rigid than the outer portion. Alternatively orin combination, an optically clear inner portion can be molded; theinner portion placed in the mold, and the covering molded to form theouter portion around the inner portion. For example, the molded innerportion comprising layer 110L2 of material 110M2 as described herein,and one or more of layers 110L1 or 110L3 molded around layer 110L2.

It should be appreciated that the specific steps illustrated in Method500 provide a particular method of manufacturing a covering, accordingto an embodiment of the present invention. Other sequences of steps mayalso be performed according to alternative embodiments. For example,alternative embodiments of the present invention may perform the stepsoutlined above in a different order. Moreover, the individual stepsillustrated may include multiple sub-steps that may be performed invarious sequences as appropriate to the individual step. Furthermore,additional steps may be added or removed depending on the particularapplications. One of ordinary skill in the art would recognize manyvariations, modifications, and alternatives.

Clinical studies have been undertaken and are contemplated to show thepumping of the tear under the lens with blinking of the eye inaccordance with the embodiments described herein. A person of ordinaryskill in the art can determine empirically the properties of covering100 as described herein so as to provide pumping of the tear fluid underthe covering to provide one or more of an extended wear contact lens ora covering for placement on the cornea following PRK to improve visionand promote reepithelialization.

As used herein, like reference characters indicate like structures thatcan be combined in accordance with the teachings and embodimentsdescribed herein.

In certain embodiments, methods for selecting ophthalmic lenses areprovided. The methods may be used to correct a refractive error of aneye of a patient, the eye having a cornea with an epithelium providing arefractive shape. In certain embodiments, methods for selectingophthalmic lenses comprise determining a desired spherical power so asto mitigate any spherical component of the refractive error of the eyeof the patient; and identifying, from among a plurality of alternativeophthalmic lenses having differing spherical powers, the ophthalmic lenscorresponding to the desired spherical power. The identified ophthalmiclens may then be selected and applied to the eye of the patient tocorrect the spherical refractive error. The identified ophthalmic lenshas an anterior surface corresponding to the desired optical power, andthe anterior surface extends along an inner portion of the ophthalmiclens.

The ophthalmic lenses have an inner portion for correcting sphericalrefractive error and a peripheral portion for contacting an opticaltissue. The inner portion of the ophthalmic lens is deformable and theperipheral portion of the ophthalmic lens is deformable. The innerportion of the ophthalmic lens has a modulus and a rigidity that ishigher than the modulus and the rigidity of the peripheral portion. Theperipheral portion of the ophthalmic lens has a shape suitable forengaging the eye outside the optical region so as to support the innerportion in alignment with an optical region of the eye. In certainembodiments, the peripheral portion is configured to engage a tissue ofthe eye such as the epithelium and to prevent or minimize motion of theophthalmic device with respect to the optical region of the eye. Incertain embodiments, the inner portion, the peripheral portion, or boththe inner and peripheral portions may deform or deflect upon blinking ofthe eye.

In certain embodiments, the refractive shape of the epithelium extendsacross the optical region of the eye such that the refractive errorcomprises astigmatism and/or a high-order optical aberration. In suchembodiments, the posterior surface extending across the optical regionadjacent the eye may or may not comprise a refractive shape so as tomitigate the astigmatism and/or high-order aberration. Selection of adesired ophthalmic lens is performed so that the peripheral portion ofthe ophthalmic lens has a suitable shape to maintain a lenticular volumebetween the posterior surface of the ophthalmic device and the surfaceof the eye such as the epithelium. Before, during, and/or followingpositioning of the ophthalmic device on the eye, the lenticular volumefills with tear fluid such that the anterior shape of the ophthalmiclens corrects the refractive error. Accordingly, in certain methods,selecting an ophthalmic lens is performed so that the peripheral portionhas a suitable shape such that tear fluid will fill a lenticular volumebetween the posterior surface and the refractive shape of the eye so asto mitigate the astigmatism and/or high-order aberration. Where tearfluid is disposed between the contact lens and the eye, and where thelens has a refractive index sufficiently close to that of the tearfluid, the refraction of the eye may be largely independent of the shapethe posterior surface and/or lenticular volume, at least when theposterior surface initially contacts the lens and/or the contact lensremains disposed on the eye. In certain methods, identifying anophthalmic lens is independent of as least one member of the group apower of the astigmatism; and orientation of the astigmatism about anoptical axis of the eye, and/or as strength of the high-order aberrationand/or a type of high-order aberration. As a consequence of thelenticular volume as defined by posterior surface of the eye and therefractive shape being filled with tear fluid, it is not necessary toorient an axis or position of the ophthalmic device with the eye.

Ophthalmic lens provided by the present disclosure may also be used fortreating presbyopia. Methods for treating presbyopia comprise, forexample, positioning an ophthalmic lens on an eye so that an innerportion of the ophthalmic lens is disposed over the optical region ofthe cornea of the eye, and supporting the inner portion of theophthalmic lens by engagement between a peripheral portion of theophthalmic lens and a tissue of the eye outside the optical region. Theinner portion of the ophthalmic lens and the peripheral portion of theophthalmic lens can be deformable such that the inner portion has amodulus and rigidity that is greater than the modulus and rigidity ofthe peripheral portion. To correct for presbyopia, the inner portioncomprises a presbyopia-mitigating refractive shape. In certainembodiments, a presbyopia-mitigating shape is selected from an addregion, a multifocal shape, an aspherical shape, and a combination ofany of the foregoing. In certain embodiments, the peripheral portioncomprises one or more radius of curvature configured to engage a tissueof the eye such as the epithelium so as to prevent or minimize motion ofthe inner portion with respect to the optical region of the cornea. Theanterior portion of ophthalmic lens and the posterior surface of the eyedefine a lenticular volume that is configured to fill with tear fluid.To facilitate filling and/or flow of the tear fluid a plurality offenestrations extending through the thickness of the peripheral regionmay be disposed in the peripheral region. The fenestrations are disposedso as to facilitate, in conjunction with motion of the ophthalmic lens,transfer of tear fluid through the lenticular volume. Such methods oftreating presbyopia using an ophthalmic lens provided by the presentdisclosure may not require precise alignment of the ophthalmic lens withrespect to the eye.

Similarly, methods for correcting a refractive error of an eye, such asastigmatism and/or spherical aberration, where the eye has a cornea withan epithelium providing a refractive shape extending a cross an opticalregion of the eye are also provided. Methods for correcting a refractiveerror comprising positioning an ophthalmic lens on the eye so that aninner portion of the ophthalmic lens is disposed over the optical regionof the cornea, wherein a posterior surface of the positioned ophthalmiclens extends adjacent the eye and has shape diverging from therefractive shape of the epithelium so that a lenticular volume isdisposed between the posterior surface and the epithelium. A peripheralportion of the ophthalmic lens may comprise a plurality of fenestrationsextending through the thickness of the peripheral portion and allowingpassage of tear fluid between the lenticular volume and the posterior(outer) surface of the ophthalmic lens. In such embodiments, the innerportion of the positioned ophthalmic lens is supported by engagement ofa peripheral portion of the ophthalmic lens and a tissue of the eye suchas the epithelium outside the optical region. The peripheral portion isconfigured to support the inner portion of the ophthalmic lens, toprevent or minimize motion of the inner portion with respect to theoptical region of the eye, and to facilitate filling of the lenticularvolume with tear fluid.

The fenestrations may be disposed outside the optical region of theophthalmic lens and inward of a region of engagement between theperipheral portion of the ophthalmic lens and a tissue of the eye. Theinner portion and the peripheral portion of the ophthalmic lens aredeformable, for example, deformable upon motion of an eyelid and/or overlocally protruding epithelial regions so as to inhibit pain, such thatthe inner portion has a modulus and rigidity that is higher than themodulus and rigidity of the peripheral portion. In certain embodiments,the deformability of the inner portion and the outer portion of theophthalmic lens are configured so that blinking of the eye induces flowof tear fluid through the fenestrations into and out of the lenticularvolume, and that when the eye is not blinking the inner portion retainsa shape that corrects the refractive error of the eye.

In certain embodiments, the peripheral portion comprises one or moreradius of curvature configured to engage a surface of the eye andthereby resist motion of the inner portion with respect to the opticalregion of the eye. For example, in certain embodiments, a peripheralportion comprises a plurality of radii of curvature wherein the radii ofcurvature become smaller from the center of the ophthalmic lens towardthe periphery. In certain embodiments, the engagement between theperipheral portion and the tissue surface of the eye along theengagement region inhibits lateral movement of the inner portionrelative to the cornea during blinking.

In certain embodiments, methods of correcting refractive error providedby the present disclosure can, for example, mitigate the refractiveerror, when viewing with the eye through the anterior surface,substantially independent of a shape of the lenticular volume throughouta range of astigmatic errors of at least about 0.5 D, at least about 1.0D, and in certain embodiments, at least bout 1.5 D, and is independentof a rotational orientation of the ophthalmic lens about a viewing axisof the eye.

Methods provided by the present disclosure further comprise methods ofremodeling the shape of the epithelium of an eye. In certainembodiments, methods for optically remodeling the relative shape of theepithelium comprise positioning an ophthalmic lens on the eye so that aninner portion of the ophthalmic lens is disposed over the optical regionof the cornea, wherein a posterior surface of the positioned ophthalmiclens extends adjacent the eye and has a shape diverging from therefractive shape of the epithelium so that a lenticular volume isdisposed therebetween; and supporting the inner portion of theophthalmic lens by engagement between a peripheral portion of theophthalmic lens and the eye outside the optical region so that fluidfills the lenticular volume and viewing with the eye through an anteriorsurface of the ophthalmic lens mitigates the refractive error. Inmethods of remodeling the shape of the epithelium to correct refractiveerror of the eye, the ophthalmic lens often (though not always) does notcomprise fenestrations. The posterior surface of the ophthalmic lensdefines a refractive shape for correcting spherical power and whenpositioned on the eye defines a lenticular volume with the surface ofthe eye. Over time, the epithelium and/or underlying tissue of the eyemay fill or otherwise occupy some, most, or all of the lenticular volumedisposed over the optical region. As with other embodiments anophthalmic lens for use in remodeling the shape of the epitheliumcomprises a deformable inner portion and a deformable peripheral portionsuch that the inner portion has a higher modulus and rigidity than thatof the peripheral portion and the peripheral portion is configured toengage a tissue surface of the eye and to inhibit lateral movement ofthe inner portion with respect to the optical region of the cornea.

In certain embodiments, methods of remodeling the refractive shape ofthe epithelium mitigate the refractive error when viewing with the eyethrough the anterior surface, substantially independent of a shape ofthe lenticular volume throughout a range of astigmatic errors of atleast about 0.5 D, at least about 1.0 D, and in certain embodiments, atleast bout 1.5 D, and is independent of a rotational orientation of theophthalmic lens about a viewing axis of the eye.

Furthermore, when the ophthalmic lens is removed from the eye theoptical remodeling of the epithelium mitigates the refractive error ofthe eye by at least about 1½ D at least about 8 hours, at least about 24hours, and in certain embodiments, at least about 48 hours, afterremoval of the ophthalmic lens from the eye.

Certain embodiments provided by the present disclosure comprise sets ofalternatively selectable ophthalmic lenses for correcting refractiveerrors of eyes of a population of patients. Such sets of ophthalmiclenses may be used in the methods disclosed herein. The pluralityalternative ophthalmic lenses have differing spherical powersrepresenting different refractive corrections. Each of the plurality ofalternative ophthalmic lenses comprises an anterior surfacecorresponding to an associated desired spherical power, the anteriorsurface extending along an inner portion of the ophthalmic lens, whereinthe inner portion of the ophthalmic lens is deformable; and a peripheralportion of the ophthalmic lens extending radially outwardly from theinner portion, the peripheral portion having a rigidity lower than thatof the inner portion and configured for engaging tissue outside theoptical region so as to support the inner portion in alignment with anoptical region.

In certain embodiments, ophthalmic lenses suitable for use in methodsprovided by the present disclosure comprise an inner portion configuredto be disposed over the optical region of the cornea of an eye, and aperipheral portion configured to support the inner portion of theophthalmic lens by engagement between the peripheral portion of a tissueof an eye such as an epithelium disposed outside the optical region. Theinner portion and the peripheral portion are deformable such that themodulus and rigidity of the inner portion is higher than that of theperipheral portion. In certain embodiments, the peripheral portioncomprises one or more radii of curvature whereby the peripheral portionengages a surface tissue of an eye to prevent or mitigate motion of theinner portion with respect to the optical region of the cornea duringblinking.

For treatment of presbyopia, the inner portion of the ophthalmic lenscomprises a surface extending along the inner portion comprising apresbyopia-mitigating refractive shape.

For treatment of spherical refractive error the surface extending alongthe inner portion of the ophthalmic lens comprises a shape configure tocorrect spherical refractive error.

In certain embodiments, the inner portion may be configured to correctnon-spherical refractive errors such as astigmatic error, multifocalerror, higher order aberrations, and custom optically correctivefunctions such as pin holes.

Certain embodiments provided by the present disclosure include coveringscomprising an optical component and a coupling component, the opticalcomponent comprising a first material having a first modulus, and thecoupling component comprising a second material having a second modulus,wherein the first modulus is greater than the second modulus. FIG. 5shows covering 500, comprising optical component 501 and couplingcomponent 502.

In certain embodiments, covering 500 has a diameter 510 from about 9 mmto about 16 mm, in certain embodiments, from about 10 mm to about 15 mm,and in certain embodiments, from about 12 mm to about 14 mm.

In certain embodiments, optical component 501 comprises a centerthickness from about 150 μm to about 500 μm, from about 200 μm to about400 μm, and in certain embodiments, from about 250 μm to about 350 μm.

In certain embodiments, optical component 501 comprises a first materialhaving a first thickness 505 and a second material having a secondthickness 503. In such embodiments, the second material may be disposedon the inner surface of optical component 501, e.g., the surface facingthe cornea, and may be the same material as the material formingcoupling component 502. The second material may have a thickness 503from about 5 μm to about 60 μm, from about 10 μm to about 50 μm, and incertain embodiments, from about 20 μm to about 40 μm. In suchembodiments, where optical component 501 comprises two materials, thetotal thickness of the optical component may be from about 100 μm toabout 550 μm, from about 200 μm to about 450 μm, and in certainembodiments, from about 250 μm to about 350 μm.

In certain embodiments, optical component 501 comprises an opticallyclear material having a modulus from about 10 MPa to about 70 MPa, fromabout 20 MPa to about 60 MPa, from about 20 MPa to about 50 MPa, and incertain embodiments from about 30 MPa to about 40 MPa.

Optical component 501 may be configured to correct vision or may not beconfigured to correct vision.

In certain embodiments, optical component 501 comprises a materialselected from silicone, silicone hydrogel, and a combination thereof. Incertain embodiments, optical component 501 comprises silicone, incertain embodiments, silicone hydrogel, and in certain embodiments acombination of silicone and silicone hydrogel.

In certain embodiments, optical component 501 comprises a centerthickness from about 150 μm to about 500 μm, a diameter from about 3 mmto about 9 mm, a radius of curvature from about 7 mm to about 12 mm, anda modulus from about 20 MPa to about 50 MPa.

In certain embodiments, coupling component 502 extends from opticalcomponent 501 to an outer periphery 504, where the thickness at thejuncture with optical component 501 is the same as or similar to that ofoptical component 502, and gradually tapers toward outer periphery 504,wherein the thickness of the coupling component at the periphery us fromabout 5 μm to about 60 μm, from about 10 μm to about 50 μm, and incertain embodiments, from about 20 μm to about 40 μm.

In certain embodiments, coupling component 502 comprises at least oneradius of curvature 512. For example, in certain embodiments, couplingcomponent 502 comprises a single radius of curvature, and in certainembodiments, coupling component 502 comprises more than one radius ofcurvature such as two, three, four, five, six, or more than six radii ofcurvature. The at least one radius of curvature can be, for example,from about 5 mm to about 15 mm, from about 6 mm to about 13 mm, fromabout 7 mm to about 12 mm, and in certain embodiments, from about 6 mmto about 10 mm. The one or more radius of curvature 512 characterizingcoupling component 502 are less than the radius of curvature of opticalcomponent 501.

In certain embodiments, coupling component 502 comprises a materialhaving a modulus from about 0.05 MPa to about 4 MPa, from about 0.1 MPato about 3 MPa, from about 0.1 MPa to about 2 MPa, and in certainembodiment from about 0.2 MPa to about 1.5 MPa.

In certain embodiments, coupling component 502 comprises a materialselected from silicone, silicone hydrogel, and a combination thereof. Incertain embodiments, coupling component comprises silicone, in certainembodiments, silicone hydrogel, and in certain embodiments a combinationof silicone and silicone hydrogel.

In certain embodiments, coupling component 502 comprises a plurality offenestrations 509 extending through the thickness of the couplingcomponent. Coupling component 502 may comprise, for example, from 1 toabout 30 fenestrations, from 1 to about 20 fenestrations, and in certainembodiments, from about 1 to about 10 fenestrations. Fenestrations 509may have any suitable shape to provide egress of tear fluid. Suitableshapes include, for example, circular, elliptical, oval, rectangular,square, slot, or combination of any of the foregoing. Each of theplurality of fenestrations 509 may have the same shape or at least someof the fenestrations may have different shapes. In certain embodiments,the fenestrations have a maximum dimension (hole size) from about 50 μmto about 700 μm, from about 100 μm to about 500 μm, and in certainembodiments, from about 200 μm to about 400 μm. Each of thefenestrations may have the same maximum dimension or at least one of thefenestrations may have a different dimension.

In certain embodiments, coupling component 502 does not includefenestrations.

In certain embodiments, coupling component 502 comprises a thicknesstapering from the thickness of optical component 501 to a thickness ofabout 30 μm at the periphery 504 of the coupling component; a pluralityor radius of curvature from about 7 mm to about 12 mm; and comprises amaterial having a modulus from about 0.1 MPa to about 2 MPa. Inembodiments in which coupling component 502 comprises a plurality ofradii of curvatures 512, the radius of curvature decreases from theoptical component toward the periphery.

The covering, including optical component 501 and coupling component502, is configured to provide a seal to a tissue of an eye such as anepithelium to thereby resist movement of the optical component on aneye.

FIGS. 6A-6C show various lenses positioned on an astigmatic eye. Foreach of FIGS. 6A-6C, the left image shows the configuration of the firstradial and the right image shows the configuration of the second radialcorresponding to the aspheric projection 608. In FIG. 6A, theconfiguration corresponding to the first radial includes the opticalsurface of the eye 601 and soft refractive lens 603, which provides afocus on retina 605. In the right image of FIG. 6A, the second radialdirection corresponds to a different refractive shape 602 that does notfocus on the retina. Soft, conformable ophthalmic lens 604 conforms toshape 602 and thereby fails to correct the non-spherical aberration.FIG. 6B shows aspheric correction using a hard, non-conformableophthalmic lens 606. Again, the first radial and the second radialcorrespond to different optical shapes 601 and 602, respectively.Although hard ophthalmic lens 606 corrects vision, the lens must beoriented to correct the asymmetric profile of the eye. FIG. 6Cschematically shows correction of non-spherical aberration usingophthalmic lenses and methods provided by the present disclosure (withthe peripheral portion of the eye and lens outside the optical regionomitted for simplicity). Ophthalmic lenses provided by the presentdisclosure have a modulus and rigidity that is configured to provide alenticular volume between the optical surface of the eye 602 and theophthalmic lens 607. For correction of presbyopia, the ophthalmic lensis configured such that the lenticular volume fills with tear fluid. Ascan be appreciated, it is not necessary to orient ophthalmic lens 607 tocorrect non-spherical optical aberrations.

Coverings provided by the present disclosure may be used as platforms ina number of ophthalmic applications including, for example, epitheliumhealing, spherical correction of astigmatism, presbyopic solutions,epithelial reshaping, and dry eye.

In certain embodiments, coverings may be used to facilitate epithelialhealing. Epithelial defects can occur, for example, as the result ofPRK, filamentary keratitis, evaporative dry eye, or physical injury tothe eye. In these and other applications, including applications inwhich vision is corrected,

When positioned on the eye of a patient, the inner surface of thecovering and the outer surface of the eye, which may include, forexample, the cornea, Bowman's membrane, and/or epithelium, can define achamber to facilitate healing and/or growth of the epithelium. In suchapplications it is desirable that a covering control moisture contentand exhibit a high Dk to facilitate extended wear. Using coverings andmethods provided by the present disclosure, complete epithelial regrowthfollowing PRK surgery can occur within about 48 hours, about 72 hours,96 hours, and in for certain patients, within about 1 week followingPRK.

When used for spherical correction of corneal astigmatism, coverings andmethods provided by the present disclosure exhibit the advantages ofimproved comfort compared to gas permeable lenses, enhanced visioncompared to soft contact lenses, and reduced fitting time compared totoric and GP lenses. Coverings and methods can, in certain embodiments,correct greater than 95% of astigmatic errors, irregular astigmatismsuch as induced by trauma or RK, and early kerotoconus.

In certain embodiments, a covering comprises an optical component thatcorrects vision. Thus, in addition to spherical correction, the opticalcomponent can be configured to support multifocal, higher orderaberration or custom optical designs such as pin holes.

In epithelial reshaping applications, coverings and methods provided bythe present disclosure can be used to reshape the epithelial duringwear, and correct vision for a period of time after the covering isremoved from the eye. For example, to correct myopia, a covering can beused to guide the epithelium toward the periphery of the eye and tocreate a flatter center curve. To correct hyperopia, a covering may beused to guide the epithelium toward the center of the eye and to createa steeper center curve. In certain embodiments, a covering can be usedto induce mulitfocality for vision correction by guiding the epitheliumtoward a desired location or locations on a cornea by molding with anaspheric optic. The induction of mulitfocality through epithelialreshaping can be useful to correct vision in presbyopia and myopia.

Coverings and methods provided by the present disclosure can also beused to address dry eye. In such applications, the covering materialcomprises a material such as silicone that has a low water content andlow water absorption, water evaporation from the eye can be controlledand a tear or lubricant reservoir maintained.

EXAMPLES

Embodiments provided by the present disclosure are further illustratedby reference to the following examples, which describe the use ofcertain ophthalmic lenses provided by the present disclosure. It will beapparent to those skilled in the art that many modifications, both tomaterials, and methods, may be practiced without departing from thescope of the disclosure.

Example 1

A subject requiring an optical correction of −2.63 Diopters (OD) and−2.13 Diopters (OS) characteristic for a subject having myopia woreophthalmic lenses on both eyes for (very roughly) about 40 hours. Theinner and peripheral radii of curvature for the ophthalmic devices areprovided in Table 1. After about 40 hours, the ophthalmic lenses wereremoved and the amount of optical correction (Diopters) need to correctvision was determined at various times. The amount of optical correction(Diopters) needed after the ophthalmic lens was removed from thesubjects is presented in Table 1.

TABLE 1 Amount of optical correction (Diopters) needed after wearing anophthalmic lens. Amount of Radii of correction curvature for neededophthalmic lens (prior to Inner Peripheral shield Curve Curve Timefollowing ophthalmic lens removal wear) (degrees) (degrees) 5 min 2 hr 4hr 8 hr 24 hr 30 hr 48 hr Subject −2.63 39.5 43.0 −0.63 +0.13 +0.13 NM−0.50 −0.75 −1.25 #1 OD Subject −2.13 39.5 41.5 −0.63 −0.13 NM NM 0.000.00 −2.38 #1 OS *NM = No Measurement

Example 2

A subject requiring an optical correction of +0.13 Diopters (OD) and+0.25 Diopters (OS) characteristic for a subject having hyperopia woreophthalmic lenses on the right eye for (very roughly) about 35 hours,and on the left eye for (very roughly) about 17. The inner andperipheral radii of curvature for the ophthalmic devices are provided inTable 2. After about the specified number of hours, the ophthalmiclenses were removed and the amount of optical correction (Diopters) needto correct vision was determined at various times. The amount of opticalcorrection (Diopters) needed after the ophthalmic lens was removed fromthe subjects is presented in Table 2.

TABLE 2 Amount of optical correction (Diopters) needed after wearing anophthalmic lens. Amount of Radii of correction curvature for neededophthalmic lens (prior to Inner Peripheral shield Curve Curve Timefollowing ophthalmic lens removal wear) (degrees) (degrees) 5 min 2 hr 4hr 8 hr 24 hr 30 hr 48 hr Subject +0.13 39.5 43.0 −2.38 −3.13 −3.37−2.00 NM NM NM #2 OD Sub j ect +0.25 39.5 41.5 −1.00 −1.25 NM NM 0.00 NMNM #2OS *NM = No Measurement

While the exemplary embodiments have been described in some detail, byway of example and for clarity of understanding, those of skill in theart will recognize that a variety of modifications, adaptations, andchanges may be employed. Hence, the scope of the present inventionshould be limited solely by the appended claims.

APPENDIX 1

TABLE B1 R1 14 mm center R1B1 R1B2 R1B3 R1 C2 multicurve BC 5-7 mm 7-9mm 9-11 mm 13.5-14 mm SAG designs (D) K (D) K (D) K (D) K (D) mm DIASteep K 36.5 43.50 42.25 39.50 <12 mm BC (140 micron thick) 3.1-3.413.8-14.1 mm Medium 36.5 42.00 40.75 38.25 <12 mm BC (140 micron thick)3.1-3.4 13.8-14.1 mm Flat K 36.5 40.50 39.25 36.75 <12 mm BC (140 micronthick) 3.1-3.4 13.8-14.1 mm Steep K 38.5 44.25 43.00 40.25 <12 mm BC(140 micron thick) 3.1-3.4 13.8-14.1 mm Medium 38.5 42.75 41.50 39.00<12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm Flat K 38.5 41.2540.00 37.50 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm Steep K40.5 45.00 43.75 41.00 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mmMedium 40.5 43.50 42.25 39.75 <12 mm BC (140 micron thick) 3.1-3.413.8-14.1 mm Flat K 40.5 42.00 40.75 38.25 <12 mm BC (140 micron thick)3.1-3.4 13.8-14.1 mm

TABLE B2 Flatter periphery design 14 mm R1 R1B1 R1B2 R1B3 R1 C2multicurve Center 5-7 mm 7-9 mm 9-11 mm 13.5-14 mm SAG designs BC (D) K(D) K (D) K (D) K (D) (mm) DIA Steep K 36.5 43.50 42.25 38.50 <12 mm BC(140 micron thick) 3.1-3.4 13.8-14.1 mm Medium 36.5 42.00 40.75 37.25<12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm Flat K 36.5 40.5039.25 35.75 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm Steep K38.5 44.25 43.00 39.25 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mmMedium 38.5 42.75 41.50 38.00 <12 mm BC (140 micron thick) 3.1-3.413.8-14.1 mm Flat K 38.5 41.25 40.00 36.50 <12 mm BC (140 micron thick)3.1-3.4 13.8-14.1 mm Steep K 40.5 45.00 43.75 40.00 <12 mm BC (140micron thick) 3.1-3.4 13.8-14.1 mm Medium 40.5 43.50 42.25 38.75 <12 mmBC (140 micron thick) 3.1-3.4 13.8-14.1 mm Flat K 40.5 42.00 40.75 37.25<12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm

TABLE B3 Large shield (16 mm) R1 R1B1 R1B2 R1B3 multicurve center 5-7 mm7-9 mm 9-10.5 mm 10.5-13 mm SAG designs BC K (D) K (D) K (D) K (D) 13-16mm* (mm) DIA Steep K 36.5 43.50 42.25 39.50 <10.0 mm/33.75 D <14.5 mm/23D 3.6 15.6-16.1 mm Medium 36.5 42.00 40.75 38.25 <10.0 mm/33.75 D <14.5mm/23 D 3.6 15.6-16.1 mm Flat K 36.5 40.50 39.25 36.75 <10.0 mm/33.75 D<14.5 mm/23 D 3.6 15.6-16.1 mm Steep K 38.5 44.25 43.00 40.25 <10.0mm/33.75 D <14.5 mm/23 D 3.6 15.6-16.1 mm Medium 38.5 42.75 41.50 39.00<10.0 mm/33.75 D <14.5 mm/23 D 3.6 15.6-16.1 mm Flat K 38.5 41.25 40.0037.50 <10.0 mm/33.75 D <14.5 mm/23 D 3.6 15.6-16.1 mm Steep K 40.5 45.0043.75 41.00 <10.0 mm/33.75 D <14.5 mm/23 D 3.6 15.6-16.1 mm Medium 40.543.50 42.25 39.75 <10.0 mm/33.75 D <14.5 mm/23 D 3.6 15.6-16.1 mm Flat K40.5 42.00 40.75 38.25 <10.0 mm/33.75 D <14.5 mm/23 D 3.6 15.6-16.1 mm*may not tangent with previous curve (may insert an outer curve to helpit flare)

TABLE B4 R1 R1B1 R1B2 R1B3 R1C Multicurve center 5-7 mm 7-9 mm 9-11 mm13.5-14 mm SAG CL designs BC (D) K (D) K (D) K (D) K (D) (mm) DIA CLcentral Steep K 40 41.75 39.00 39.00 <12 mm BC (140 micron thick)3.1-3.4 13.8-14.1 mm curve 1 Medium 40.00 39.75 37.25 37.25 <12 mm BC(140 micron thick) 3.1-3.4 13.8-14.1 mm Flat K 40.00 37.75 35.25 35.25<12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm CL central Steep K42.00 43.75 41.00 41.00 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1mm curve 2 Medium 42.00 41.75 39.25 39.25 <12 mm BC (140 micron thick)3.1-3.4 13.8-14.1 mm Flat K 42.00 39.75 37.25 37.25 <12 mm BC (140micron thick) 3.1-3.4 13.8-14.1 mm CL central Steep K 44.000 44.75 42.0042.00 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm curve 3 Medium44.00 43.25 40.75 40.75 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1mm Flat K 44.00 41.75 39.25 39.25 <12 mm BC (140 micron thick) 3.1-3.413.8-14.1 mm CL central Steep K 46.00 46.75 44.00 44.00 <12 mm BC (140micron thick) 3.1-3.4 13.8-14.1 mm curve 4 Medium 46.00 45.25 42.7542.75 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm Flat K 46.0043.75 41.25 41.25 <12 mm BC (140 micron thick) 3.1-3.4 13.8-14.1 mm

What is claimed is:
 1. An ophthalmic lens to correct refractive error ofan eye, wherein, the eye comprises a pupil, a cornea, a conjunctiva, anda viewing axis; and the ophthalmic lens comprises: an inner opticportion configured to correct refractive error; a peripheral portionconfigured to support the inner optic portion in relation to the pupil;and fenestrations coupled to channels extending radially inward from thefenestrations along a lower surface of the ophthalmic lens; whereincorrecting refractive error is independent of rotational orientation ofthe ophthalmic lens about the viewing axis of the eye.
 2. The ophthalmiclens of claim 1, wherein the refractive error comprises astigmaticerror.
 3. The ophthalmic lens of claim 1, wherein the astigmatic erroris throughout a range of at least about 0.5 D.
 4. The ophthalmic lens ofclaim 1, wherein the astigmatic error is throughout a range of at leastabout 1.5 D.
 5. The ophthalmic lens of claim 1, wherein the refractiveerror comprises astigmatism, high-order aberration, or a combinationthereof.
 6. The ophthalmic lens of claim 1, wherein the refractive errorcomprises non-spherical optical aberrations.
 7. The ophthalmic lens ofclaim 1, wherein the non-spherical optical aberrations compriseastigmatic error, multifocal error, higher order aberrations, and customoptically corrective functions such as pinholes.
 8. The ophthalmic lensof claim 1, wherein the refractive error comprises presbyopia.
 9. Theophthalmic lens of claim 1, when applied to the eye, provides one ormore lenticular volumes between the posterior surface of the inneroptical portion and the anterior surface of the eye.
 10. The ophthalmiclens of claim 9, wherein the one more lenticular volumes comprises tearfluid.
 11. The ophthalmic lens of claim 9, when applied to the eye,refraction of the eye is independent of the shape of the posteriorsurface of the inner optical portion, the shape of the one or morelenticular volumes, or both the shape of the posterior surface of theinner optical portion and the shape of the lenticular volume.
 12. Theophthalmic lens of claim 1, wherein each of the inner optic portion andthe peripheral portion is deformable upon motion of an eyelid.
 13. Theophthalmic lens of claim 1, wherein each of the inner optical portionand the peripheral portion have a modulus and a rigidity configured toprovide a lenticular volume between the optical surface of the eye andthe ophthalmic lens.
 14. The ophthalmic lens of claim 1, wherein, theinner optical portion comprises a first material having a first modulus;the peripheral portion comprises a second material having a secondmodulus, and the first modulus is greater than the second modulus. 15.The ophthalmic lens of claim 1, wherein, the inner optical portioncomprises a first material having a first rigidity; the peripheralportion comprises a second material having a second rigidity, and thefirst rigidity is greater than the second rigidity.
 16. The ophthalmiclens of claim 1, wherein each of the inner optical portion and theperipheral component comprise a silicone, a silicone hydrogel, or acombination thereof.
 17. A method of treating refractive error of an eyeof a patient, comprising applying the ophthalmic lens of claim 1 to aneye of a patient in need of such treatment.